Chemistry MC: April 2020

A) accuracy of a measurement
B) number of digits on a calculator
C) number of measurements
D) precision of a measurement
E) accuracy of the conversion factor

Answer: D

The measurement of the gravitational pull on an object is its

A) volume
B) weight
C) mass
D) length
E) size

Answer: B

Which of the following is a measurement of mass in the metric system?

A) millimeter
B) centimeter
C) kilogram
D) Celsius
E) meter

Answer: C

Which of the following is the basic unit of mass in the SI?

A) pound
B) kilogram
C) milligram
D) microgram
E) gram

Answer: B

The metric unit for volume is the

A) meter
B) quart
C) liter
D) pint
E) centimeter

Answer: C

The metric base unit for length is the

A) meter
B) inch
C) millimeter
D) kilometer
E) foot

Answer: A

Written in scientific notation 0.00000033 is

A) 3.3 x 10^7
B) 3.3 x 10-7
C) 3.3 x 10^8
D) 3.3 x 10^-8
E) 3.3

Answer: B

Written in scientific notation 8300 is

A) 8.3 x 10^2
B) 8.3 x 10^3
C) 8.3 x 10^4
D) 8.3 x 10^-3
E) 8.3 x 10^-2

Answer: B

Written in scientific notation, 540,000 is

A) 0.54 x 10^6
B) 54 x 10^8
C) 5.4 x 10^-5
D) 5.4 x 10^5
E) 5.4

Answer: D

16 is what percent of 80

A) 200%
B) 20%
C) 2%
D) 5%
E) 50%

Answer: B

12 is what percent of 36

A) 3%
B) 30%
C) 33%
D) 330%
E) 12%

Answer: C

Which of the following would not be part of a study plan to learn chemistry?

A) study a little everyday
B) skip your instructors study hours
C) form a study group
D) read the chapter before class
E) work the sample problems

Answer: B

In order to enhance your learning in chemistry, you should not

A) study a little everyday
B) form a study group
C) go to office hours
D) be an active learner
E) wait until the night before the exam to study

Answer: E

One way to enhance your learning in chemistry is to

A) study a little everyday
B) form a study group
C) go to office hours
D) be an active learner
E) all of the above

Answer: E

There is more traffic between 8 and 9 in the morning because most people start work at 9. This would be a

A) observation
B) hypothesis
C) experiment
D) theory
E) all of the above

Answer: B

You notice that there is more traffic between 8 and 9 in the morning. This would be a

A) observation
B) hypothesis
C) experiment
D) theory
E) all of the above

Answer: A

Which of the following is a chemical?

A) sugar
B) heat
C) light
D) noise
E) a wave

Answer: A

When a part of the body is injured, substances called _____ are released.

A) aspirins
B) pain relievers
C) nitrogen oxides
D) chlorofluorocarbons
E) prostaglandins

Answer: E

Titanium dioxide is a chemical used in toothpaste to

A) make the paste white
B) disinfect the toothbrush
C) keep the paste from spoiling
D) remove plaque
E) strengthen tooth enamel

Answer: A

Sodium fluoroscope is a chemical used in toothpaste to

A) make the paste white
B) disinfect the toothbrush
C) keep the paste from spoiling
D) remove plaque
E) strengthen tooth enamel

Answer: E

Which of the following is not a chemical?

A) salt
B) water
C) light
D) carbon dioxide
E) sugar

Answer: C

One example of a chemical used in toothpaste is

A) chlorine
B) sulfur
C) carbon dioxide
D) calcium carbonate
E) sugar

Answer: D

In this list, which substance can be classified as a chemical?

A) salt
B) sleep
C) cold
D) heat
E) temperature

Answer: A

Water H2O is an example of

A) chemical
B) solid
C) wave
D) electric charge
E) element

Answer: A

A compound of sodium and oxygen has 58.96% Na and a molar mass of 77.98 g/mol. What is the molecular formula of the compound?

A) Na2O
B) NaO
C) NaO2
D) Na2O2
E) Na2O3

Answer: D

You combine 6.54g of Zn with oxygen and find a while powder, ZnxOy with a mass of 8.14g the empirical formula of the product is

A) ZnO
B) Zn2O
C) ZnO2
D) Zn2O3

Answer: A

A hydrocarbon has the empirical formula CH2. If it's molar mass is 140.3 g/mol, what is its molecular formula?

A) CH2
B) C5H10
C) C8H15
D) C10H20

Answer: D

All of the following statements regarding 57.1 g of octane, C8H18 are true except

A) 57.1g is 0.5 mol of octane
B) the compound has 84.1% C by weight
C) the empirical formula of the compound is C4H9
D) 57.1g of octane contains 28.0g of hydrogen atoms

Answer: D

The simplest carbohydrate is glyceraldehyde. It's empirical formula is CH2O and it's molar mass is 90.08 g/mol. The molecular formula is

A) CH2O
B) C2H4O2
C) C3H6O3
D) C4H8O4

Answer: C

The formula of the hydrocarbon decane is C10H22. The empirical formula is

A) CH2
B) C2H4
C) C5H11
D) C10H22

Answer: C

Nitrogen and oxygen form a serious of oxides with the general formula NxOy. One of them has 46.67% N. The empirical formula for this oxide is

A) N2O
B) NO
C) NO2
D) N2O3
E) N2O5

Answer: B

Nickel silver is the name for various silver white alloys of copper, zinc and nickel (no silver). A 35.452g sample of nickel silver contained 12.5% nickel. What was the mass of the nickel in this sample?

A) 35.452g
B) 31.0g
C) 22.952g
D) 4.43g

Answer: D

Calculate the (mass) percentage of nitrogen, N, in dinitrogen trioxide N2O3 (Atomic weights in amu= N=14.01, O=16.00)

A) 40.00%
B) 36.86%
C) 18.43%
D) 46.68%

Answer: B

Which answer best represents the (mass) percent composition of CO2?

A) 50.0% C and 50.0% O
B) 12.0% C and 88.0% O
C) 27.3% C and 72.7% O
D) 12.0% C and 32.0% O

Answer: C

The molar mass of CH4 is 16 g/mol. Which represents the greatest number of molecules of CH4?

A) 35 g
B) 1.8 mol
C) 12 g

Answer: A

What is the approximate molar mass of FeO, iron(II) oxide?

A) 56 g/mol
B) 72 g/mol
C) 896 g/mol

Answer: B

Which sample has the larger number of atoms?

A) 0.10 mol Al
B) 1.3g Si
C) 0.090 mol Fe
D) 10.5g Fe
E) 3.2g S

Answer: D

You have 0.25 mol of each of the following elements. Which one has the largest mass?

A) Fe
B) Al
C) Zn
D) Ca
E) C

Answer: C

Which of the following elements has the larger molar mass?

A) K
B) Ne
C) As
D) Fe
E) Si

Answer: C

All of the following statements concerning ionic compounds are correct EXCEPT

A) as the ion charges increases, the attraction between the ions increases
B) ionic compounds form extended 3D networks called crystal lattices
C) ionic crystals tend to be rigid and they cleave along planes
D) positive and negative ions are attracted to each other by electrostatic forces
E) the electrostatic forces are weaker in CaO than in NaCl

Answer: E

Sodium oxalate has the formula Na2C2O4. Based on this information the formula for iron(III) oxalate is

A) FeC2O4
B) Fe(C2O4)2
C) Fe(C2O4)3
D) Fe2(C2O4)3
E) Fe3(C2O4)2

Answer: D

All of the formulas below are correct EXCEPT

A) Ba(NO3)2
B) KCIO4
C) Na3N
D) Al2(SO4)3
E) Ca2HPO4

Answer: E

Which one of the list is a molecular compound?

A) LiCl lithium chloride
B) SO2 sulfur dioxide
C) AlF3 aluminum fluoride
D) Ba(NO3)2 barium nitrate
E) NaHCO3 sodium hydrogen carbonate

Answer: B

Which compound formula and name in the list is NOT correct?

A) NaHSO4 sodium hydrogen sulfate
B) CaH2PO4 calcium hydrogen phosphate
C) FeCl3 iron(III) chloride
D) NiO nickel(II) oxide
E) Cu(CH3CO2)2 copper(II) acetate

Answer: B

Which compound formula in the list is NOT correct?

A) CaSO4 calcium sulfate
B) NaNO3 sodium nitrate
C) MgI2 magnesium iodide
D) NH4PO4 ammonium phosphate
E) Ca(CIO)2 calcium hypochlorite

Answer: D

The formula of barium molybdate is BaMoO4. What is the formula of sodium molybdate?

A) Na4MoO
B) Na2MoO3
C) Na4MoO4
D) NaMoO
E) Na2MoO4

Answer: E

Which compound in the list below is NOT possible?

A) K2NO3
B) CaSO4
C) Fe(CIO4)2
D) Na3PO4
E) LiHSO4

Answer: A

Which compound in the following list is NOT possible?

A) CaBr2
B) KI
C) Al2O
D) LiCl
E) MgO

Answer: C

The ion CIO- has

A) 25 protons and 25 electrons
B) 25 protons and 26 electrons
C) 25 protons and 24 electrons
D) 26 protons and 25 electrons
E) 26 protons and 26 electrons

Answer: B

Which of the following series contains only known nonmetal anions?

A) S2-, Br-, Al3+
B) N2-, I-, O2-
C) P3-, F-, Se2-
D) Cl-, Fe3+, S2-
E) In+, Br2-, Te2-

Answer: C

When the ion Sr2+ forms,

A) the Sr atom loses 1 electron and now has the same number of electrons as Kr
B) the Sr atom loses 1 electron and now has the same number of electrons as Xe
C) the Sr atom loses 2 electrons and now has the same number of electrons as Kr
D) the Sr atom gains 2 electrons and now has the same number of electrons as Kr
E) the Sr atom loses 3 electrons and now has the same number of electrons as Kr

Answer: C

Which group of ions contains only ions you would predict as "stable"?

A) Li2+, Fe2+, Ca2+
B) Mg3+, Cr3+, O2-
C) Ca2+, Fe3+, Al3+
D) F2-, Al4+, Na+

Answer: C

Which ion in the following list is NOT likely to form?

A) Na+
B) Mg3+
C) Al3+
D) Fe2+
E) Zn2+

Answer: B

Which statement best describes the Ca^2+ ion?

A) the cation formed when an atom of calcium gains 2 electrons
B) the cation formed when an atom of calcium loses 2 electrons
C) the anion formed when an atom of calcium gains 2 electrons
D) the anion formed when an atom of calcium loses 2 electrons

Answer: B

Which chemical property would you predict is likely for the elements Francium (Fe)?

A) it's oxide forms alkaline aqueous solutions
B) it is likely to form stable ionic compounds with sodium cations (Na+)
C) it will react vigorously with water to form hydrogen gas and a alkaline aqueous solution
D) it exists as a diatomic has under ambient conditions

Answer: C

Which element is an alkaline earth metal?

A) hydrogen
B) aluminum
C) lithium
D) calcium
E) radon

Answer: D

Which list of elements includes those in the same period or row of the periodic table?

A) Mg, Fe, Al
B) Ti, B, Ge
C) B, Al, TI
D) Cl, Si, Sn
E) Fe, Co, Ni

Answer: E

Which list of elements includes those in the same periodic group?

A) Mg, Fe, Al
B) Ti, B, Ge
C) B, Al, TI
D) Cl, Si, Sn
E) Fe, Co, Ni

Answer: C

Bromine (Br) has two stable isotopes, ^79Br and ^81Br and ^79Br has an isotopic mass of 78.918 u and an abundance of 50.69%. What is the isotopic mass of ^81Br?

A) 79.90u
B) 80.92u
C) 81.00u
D) 35.00u
E) not enough information is provided to solve this problem

Answer: B

Which is likely the most abundant stable isotope of gallium (Ga)?

A) ^69Ga
B) ^71Ga
C) Tm-169
D) Lu-175
E) ^67Ga (decay half life = 3.3 d by gamma emission)

Answer: A

Which statement describes the composition of an isotope of iron, ^58Fe?

A) 26 neutrons, 32 protons, 26 electrons
B) 32 neutrons, 26 protons, 26 electrons
C) 26 neutrons, 26 protons, 32 electrons
D) 26 neutrons, 26 protons, 26 electrons

Answer: B

Of the three major subatomic particles, the least massive is

A) proton
B) electron
C) neutron

Answer: B

How are chlorine-37 and calcium-40 similar?

A) # of protons
B) # of electrons
C) # of neutrons
D) no similarity

Answer: C

How are chlorine-37 and calcium-40 similar?

A) # of protons
B) # of electrons
C) # of neutrons
D) no similarity

Answer: C

Which of the following is true?

A) Boron-10 has 10 e
B) Boron-11 has 11 n
C) Boron-10 has 5 e
D) Boron-11 has 11 p

Answer: C

A piece of a polypropylene rope floats on water, whereas a terephthalate polymer from a soda bottle sinks in water. What is the order of increasing density of these substances?

A) water< polypropylene< soda bottle< plastic
B) polypropylene< water< soda bottle< plastic
C) polypropylene< soda bottle< plastic< water
D) soda bottle< plastic< polypropylene< water
E) soda bottle plastic< water< polypropylene

Answer: B

Which of the following is not a physical change?

A) freezing of a liquid to form a solid
B) dissolving a solid in water to form a solution
C) burning a piece of paper
D) evaporating water to steam
E) sublimation of ice to water vapor

Answer: C) burning a piece of paper

Which of the following is not a compound?

A) salt
B) water
C) potassium
D) sugar
E) alcohol

Answer: C) potassium

Which of the following is not an element?

A. Hydrogen
B. Lithium
C. Iron
D. Water
E. Silver

Answer: D. Water

Explain how a pure metal is held together. Include a definition of a metallic bond in your explanation.

Answer: A piece of pure metal, such as copper or iron, consists not of metal atoms, but of closely packed cations. The cations are surrounded by mobile valence electrons that are free to drift from one part of the metal to another. Metallic bonds result from the attraction between the free-floating valence electrons and the positively charged metal ions.

Describe the trends in the atomic size of elements within groups and across periods in the periodic table. Provide examples.

Answer: Atomic size increases with increasing atomic number within a group. For example, sodium atoms are larger than lithium atoms, and potassium atoms are larger than sodium atoms. Atomic size decreases with increasing atomic number across a period. For example, lithium atoms are larger than beryllium atoms, and beryllium atoms are larger than boron atoms.

Describe the trends in electromagnetically within groups and across periods in the periodic table. Provide examples.

Answer: Electronegativity values decrease from top to bottom within a group, and from right to left across a period. For example, rubidium is less electronegative than lithium. Lithium is less electronegative than fluorine.

How many electrons does a gallium atom give up when it becomes an ion?

Answer: 3

How many electrons are in a rubidium ion (Rb⁺)?

Answer: 36

How many valence electrons are in silicon?

Answer: 4

In 1829, the German chemist J. R. Dobereiner published a classification system in which elements were put into groups according to their properties. How many elements did he put in each of his groups?

Answer: 3

What is the coordination number of both ions in the cesium chloride crystal?

Answer: 8

Give the electron configurations for iodine and its 1- ion.

Answer: I [Kr] 5s² 4d¹⁰ 5p⁵

Which group of elements in the periodic table is known as the alkaline earths?

Answer: 2A

Write the formula for the compound rubidium phosphate.

Answer: Rb₃P

Which of the following elements is a transition metal?

a. tellurium
b. tin
c. copper
d. cesium

Answer: copper

Which of the following statements correctly compares the relative size of an ion to its neutral atom?

a. The radius of an anion is greater than the radius of its neutral atom.
b. The radius of a cation is greater than the radius of its neutral atom.
c. The radius of an anion is identical to the radius of its neutral atom.
d. The radius of a cation is identical to the radius of its neutral atom.

Answer: The radius of an anion is greater than the radius of its neutral atom.

By 1700, how many elements had scientists discovered and isolated?

a. 27
b. 46
c. 13
d. 7

Answer: 13

What is the formula of the ion formed when potassium achieves noble-gas electron configuration?

a. K⁻
b. K²⁻
c. K²⁺
d. K⁺

Answer: K⁺

The metals in Groups 1A, 2A, and 3A

a. gain electrons when they form ions.
b. all form ions with a negative charge.
c. all have ions with a 1 charge.
d. lose electrons when they form ions.

Answer: lose electrons when they form ions.

Most ionic compounds

a. conduct an electric current in the solid state.
b. have low melting points.
c. are composed of nonmetallic elements.
d. are crystalline solids at room temperature.

Answer: are crystalline solids at room temperature.

What is the electron configuration of the calcium ion?

Answer: 1s²2s²2p⁶3s²3p⁶

Which of the following elements has the smallest atomic radius?

a. sulfur
b. bromine
c. selenium
d. chlorine

Answer: chlorine

Which of the following categories includes the majority of the elements?

a. metals
b. liquids
c. nonmetals
d. metalloids

Answer: metals

Alloys are important because

a. they never corrode.
b. they are less expensive to produce than their component elements.
c. their properties are a blend of their component elements.
d. their properties are often superior to those of their component elements.

Answer: their properties are often superior to those of their component elements.

Which of the following is true about the melting temperature of potassium chloride?

a. The melting temperature is relatively high.
b. The melting temperature is variable and unpredictable.
c. The melting temperature is relatively low.
d. Potassium chloride does not melt.

Answer: The melting temperature is relatively high.

Which statement is true about electromagnetically?

a. Electronegativity is the ability of an anion to attract another anion.
b. Electronegativity generally is higher for metals than for nonmetals.
c. Electronegativity generally increases from left to right across a period.
d. Electronegativity generally increases as you move from top to bottom within a group.

Answer: Electronegativity generally increases from left to right across a period.

What is the net charge of the ionic compound calcium fluoride?

a. 2-
b. 0
c. 1-
d. 1+

Answer: 0

How many valence electrons does a helium atom have?

a. 2
b. 4
c. 3
d. 5

Answer: 2

How many electrons does nitrogen gain in order to achieve a noble-gas electron configuration?

a. 1
b. 4
c. 2
d. 3

Answer: 3

To what category of elements does an element belong if it is a good conductor of electricity?

a. halogens
b. metals
c. metalloids
d. nonmetals

Answer: metals

Of the elements Fe, Hg, U, and Te, which is a representative element?

a. Fe
b. U
c. Hg
d. Te

Answer: Te

Which of the following factors contributes to the decrease in ionization energy within a group in the periodic table as the atomic number increases?

a. increase in number of protons
b. increase in atomic size
c. fewer electrons in the highest occupied energy level
d. increase in size of the nucleus

Answer: increase in atomic size

Which of the following factors contributes to the increase in ionization energy from left to right across a period?

a. an increase in the number of protons
b. an increase in the size of the nucleus
c. fewer electrons in the highest occupied energy level
d. an increase in the shielding effect

Answer: an increase in the number of protons

What is the charge on the cation in the ionic compound sodium sulfide?

a. 1+
b. 3+
c. 0
d. 2+

Answer: 1+

How many valence electrons are transferred from the nitrogen atom to potassium in the formation of the compound potassium nitrite?

a. 3
b. 2
c. 1
d. 0

Answer: 0

What is the element with the lowest electromagnetically value?

a. helium
b. calcium
c. cesium
d. fluorine

Answer: cesium

As you move from left to right across the second period of the periodic table

a. ionization energy increases.
b. atomic radii increase.
c. electronegativity decreases.
d. atomic mass decreases.

Answer: ionization energy increases.

What characteristic of metals makes them good electrical conductors?

a. Their crystal structures can be rearranged easily.
b. They have mobile protons.
c. They have mobile cations.
d. They have mobile valence electrons.

Answer: They have mobile valence electrons

How does oxygen obey the octet rule when reacting to form compounds?

a. It does not change its number of electrons.
b. Oxygen does not obey the octet rule.
c. It gains electrons.
d. It gives up electrons

Answer: It gives up electrons

Explain the difference between the Celsius and Kelvin temperature scales.

Answer: Both scales use the freezing point and boiling point of water as reference temperatures.

The Celsius scale designates the freezing point of water as 0°C and the boiling point as 100°C. The region between these two points is divided into equal intervals called degrees. The Kelvin scale designates 0 K as the temperature at which the volume of an ideal gas would be zero. It is called the absolute zero because it is the lowest temperature that is theoretically attainable. Absolute zero corresponds to -273°C on the Celsius scale.

The Kelvin scale uses degree intervals that are the same size as the intervals on the Celsius scale. The difference between the scales lies in how the zero point is chosen. On the Celsius scale, the zero point is the freezing point of water. On the Kelvin scale, it is the point at which the volume of an ideal gas would theoretically be zero.

The scales are related by the formulas: K = °C + 273 or °C = K - 273.

How did Lavoisier transform the field of chemistry in the late 1700s?

Answer: Lavoisier helped transform chemistry from a science of observation to a science of measurement. Toward this end, he developed a balance that could measure small differences in mass. He was part of a general movement toward basing conclusions on experimental evidence.

Define element and compound. Explain the difference between an element and a compound.

Answer: An element is the simplest form of matter that has a unique set of properties. A compound is a substance that contains two or more elements chemically combined in a fixed proportion. An element cannot be broken down into simpler components through chemical reactions. Compounds are substances that can be broken down into simpler substances through chemical reactions.

How many grams of liquid are produced when 34 grams of ice melt?

Answer: 34

What is the boiling point of water in degrees Celsius?

Answer: 100°C

What is the density of an object having a mass of 4.0 g and a volume of 39.0 cubic centimetres?

Answer: Density = Mass/Volume = 4.0 g/39.0 cm³ = .10g/cm³

Which field of science studies the composition and structure of matter?

a. geology
b. biology
c. physics
d. chemistry

Answer: Chemistry.

Which of the following best describes an example of applied chemistry?

a. perfecting a method for producing nylon fibres
b. determining the structure of cotton and silk
c. determining the chemical composition of a rock such as granite
d. studying chemicals containing carbon

Answer: Perfecting a method for producing nylon fibers.

What must be done to be certain that a chemical change has taken place?

a. Demonstrate that a release of energy occurred after the change.
b. Check for the production of bubbles before and after the change.
c. Demonstrate that energy was absorbed by the reactants after the change.
d. Check the composition of the sample before and after the change.

Answer: Check the composition of the sample before and after the change.

Which substance has a chemical symbol that is derived from a Latin name?

a. hydrogen
b. potassium
c. calcium
d. oxygen

Answer: Potassium.

The chief advantage of the metric system over other systems of measurement is that it ____.

a. is derived from nature itself
b. has more units
c. is in multiples of 15
d. is in multiples of 10

Answer: It is in multiples of 10

The step that usually comes first in solving numeric problems is ____.

a. analyze
b. calculate
c. measure
d. evaluate

Answer: Analyze

How many significant figures are in the measurement 0.003 4 kg?

a. two
b. This cannot be determined.
c. four
d. five

Answer: Two

In a chemical reaction, the type of products obtained is largely determined by which part of the reacting chemicals?

a. neutrons
b. protons
c. electrons
d. nuclei

Answer: Electrons

If a liter of water is heated from 20C to 50C, what happens to its volume?

a. The volume increases.
b. The volume first increases, then decreases.
c. The volume first decreases, then increases.
d. The volume decreases.

Answer: The volume increases

Which of the following statements is false?

a. Knowledge of chemistry helps prepare people for careers in soil science.
b. Studying chemistry ensures that officials make correct choices in funding technology.
c. Chemistry explains many aspects of nature.
d. Knowledge of chemistry allows the public to make informed decisions.

Answer: Studying chemistry ensures that officials make correct choices in funding technology.

There are many reasons to study chemistry. In general, most people study chemistry for all of the following reasons EXCEPT?

a. Knowledge of chemistry is important for success in a variety of careers.
b. Chemistry can help you satisfy your natural desire to understand how things work.
c. The social prestige and honor in being a chemist.
d. Knowledge of chemistry is important in making informed decisions as a citizen

Answer: The social prestige and honor in being a chemist

Which of the following equalities is correct?

a. 10 kg =1 g
b. 1000 mm = 100 m
c. 100 cg = 10 g
d. 1 cm³ = 1 mL

Answer: 1 cm³ = 1 mL

Three different people weigh a standard mass of 2.00 g on the same balance. Each person obtains a reading of 7.32 g for the mass of the standard. These results imply that the balance that was used is ____.

a. precise
b. accurate
c. neither accurate nor precise
d. accurate and precise

Answer: Precise.

The chemical formula of a compound indicates

a. the source of the elements in the compound.
b. the relative proportions of the elements in the compound.
c. the alchemy symbols for the elements in the compound.
d. how elements are joined in the compound.

Answer: The relative proportions of the elements in the compound.

The weight of an object ____.

a. is not affected by gravity
b. is the same as its mass
c. is always the same
d. depends on its location

Answer: Depends on its location

Chlorine boils at 239K. What is the boiling point of chlorine expressed in degrees Celsius?

a. -34°C
b. -61°C
c. 93°C
d. 34°C

Answer: -34°C

Which of the following is a chemical property of water at 4°C?

a. its color
b. its state
c. its temperature
d. its ability to decompose into hydrogen and oxygen

Answer: Its ability to decompose into hydrogen and oxygen.

Which of the following is a chemical change?

a. grating cheese
b. melting cheese
c. mixing two cheeses in a bowl
d. fermenting of cheese

Answer: fermenting of cheese

Which of the following is an example of chemistry research in the main area of energy?

a. specific reactions between prescription drugs and chemicals in cells
b. determining the composition of extra-terrestrial soil and rocks.
c. producing bioplastics
d. developing rechargeable batteries

Answer: developing rechargeable batteries

When an iron nail rusts, its mass ____.

a. stays the same
b. decreases
c. increases
d. cannot be determined

Answer: increases

Which of the following measurements is expressed to three significant figures?

a. 0.070 mm
b. 7077 mg
c. 0.007 m
d. 7.30 x 10⁻⁷ km?

Answer: 7.30 x 10⁻⁷km

How many significant figures are in the measurement 811.40 grams?

a. two
b. three
c. four
d. five

Answer: Five

Which of the following is a homogeneous mixture?

a. oil in vinegar
b. alcohol in water
c. pasta in water
d. muddy water

Answer: alcohol in water

Which of the following is a homogeneous mixture?

a. soil
b. beef stew
c. sand and water
d. salt water

Answer: saltwater

A horizontal row of the periodic table is usually referred to as a

a. period.
b. family.
c. property.
d. group.

Answer: period

A central concept of the kinetic theory, one of the "big ideas" of chemistry, is the belief that

a. every chemical process uses or produces energy, often in the form of heat.
b. chemical reactions involve processes in which reactants produce products.
c. the particles in matter are in a state of constant motion.
d. for every reaction there is an eqsual and opposite reaction.

Answer: the particles in matter are in a state of constant motion

How many positive charges are there in the nucleus of a nitrogen atom?

Answer: 7

What is the name of the element with no neutrons?

Answer: Hydrogen

What is the symbol of the element found in 1.0% of the human body?

Answer: P

How many neutrons are in the nucleus of an oxygen atom?

Answer: 8 neutrons

What is the Atomic Mass of oxygen?

Answer: 16 a.m.u.

Atomic Mass is made up of what two particles?

Answer: Protons and Neutrons

How many protons does carbon have?

Answer: 6 protons

What is the Atomic Number of carbon?

Answer: 6

What is the symbol of the element that makes up 9.5% of the human body?

Answer: H

What is the name of the element that makes up 9.5% of the human body?

Answer: Hydrogen

What is the name of the least abundant element found in the human body?

Answer: Sulfur

The effects of cosmetics and beauty products are based on how _________.

Answer: the body reacts to chemicals

Everything you can touch and everything you can see is matter EXCEPT for which of the following?

Answer: Light and electricity

Acid-alkali neutralization reactions occur when an acid is mixed with an alkali in equal proportions, balancing the total pH and forming water (H2O) and _________.

Answer: a salt

Which of the following is defined as any substance that occupies space and has weight?

Answer: Matter

The Safety Data Sheet (SDS) replaced the _________.

Answer: Material Safety Data Sheet (MSDS)

______ is an example of a compound molecule.

Answer: Exposed metal rusting

During combustion of a substance, _________ accompanies the rapid oxidation.

Answer: the production of heat and light

What is the pH scale used to measure?

Answer: Acidity and alkalinity

An oxidizing agent _________ oxygen.

Answer: releases

______ is the simplest form of chemical matter.

Answer: An element

If you left the freezer door open all night at work, all of the ice you had in the freezer for after hair removal services would probably melt. This would be a result of _________.

Answer: an endothermic reaction

A solute is a _________.

Answer: substance that is dissolved in a solution

Creams, lotions, masks, and makeup _________.

Answer: contain chemicals whether they come from natural sources or from ingredients manufactured in a laboratory

How many categories are all SDSs are formatted into?

Answer: 16

When salt is dissolved into water, _________.

Answer: salt is the solute and water is the solvent

In the uniform order of the SDS, _________ comes immediately after the first category of "Identification."

Answer: Hazard Identification

Estheticians should study and have a thorough understanding of chemistry because _________.

Answer: every product used in the esthetics industry contains some type of chemical

A reducing agent _________.

Answer: adds hydrogen to a chemical compound

Understanding pH is important for the esthetician because _________.

Answer: it affects the hair, skin, and nails

What is pH is an abbreviation of?

Answer: Potential hydrogen

Among the following choices, acids would MOST likely be used to _________.

Answer: exfoliate the skin

Which of the following should you be sure to do when mixing chemicals?

Answer: Use a measuring device, such as a measuring cup or spoon.

If you were the owner of the local spa, why would it be so important that you insist that for every chemical used there is an SDS available?

Answer: Because it is a requirement of OSHA

There are _________ elements are known to science today.

Answer: 118

If your client requests that you use a solution that is neutral to his skin, which of the following pHs should you be using?

Answer: A pH of 5

_______ for the disposal of many of the chemicals used in salons or spas.

Answer: Most states and counties do not have regulations in place

A solvent is any _________.

Answer: substance that dissolves a solute and makes a solution

What do miscible liquids form when they are combined?

Answer: Suspensions

There are _________ accepted pictograms included in all SDSs.

Answer: 9

SDSs are designed for _________.

Answer: use in an emergency

Which of the following are defined as the basic units of matter?

Answer: Atoms

Which of the following is capable of igniting and burning?

Answer: A combustible

What is the name of the branch of chemistry dealing with compounds that do not contain the element carbon?

Answer: inorganic chemistry

What is the process through which oxygen is subtracted from, or hydrogen is added to, a substance through a chemical reaction?

Answer: reduction

What is a solute?

Answer: any substance that is dissolved by a solvent to form a solution

What are chemical combinations of two or more atoms of different elements called?

Answer: compound molecules

Approximately how many naturally occurring elements are there?

Answer: 90

What is an atom or molecule that carries an electrical charge?

Answer: ion

Antioxidants prevent oxidation by neutralizing what?

Answer: free radicals

What is matter that has fixed volume but no definite shape?

Answer: liquid

Why must theoreticians understand basic chemistry?

Answer: To use professional products effectively and safely

What is the most abundant element on Earth?

Answer: Oxygen

What are acids?

Answer: substances with a pH below 7.0

What is an example of something we can see that is NOT matter?

Answer: light

What is an example of an oil-in-water emulsion?

Answer: moisturizer

What is the simplest form of matter?

Answer: element

What is the natural pH of the skin?

Answer: 5.5

What occurs when an acid is mixed with an alkali in equal proportions to form water and a salt?

Answer: acid-alkali neutralization reaction

What is the chemical reaction involving the addition of oxygen or the loss of hydrogen?

Answer: oxidation

Most skin care products are emulsions of what?

Answer: oil and water

The logarithmic scale is a method of displaying data in multiples of what?

Answer: 10

Salons and spas primarily use what kind of emulsions?

Answer: oil-in-water

What would be the molar solubility of Li3PO4 (Ksp = 2.37 x 10-4) in a 1M LiCl solution?

a) 1.54 x 10^-2
b) 5.44 x 10^-2
c) 2.37 x 10^-4
d) 1.24 x 10^-1

Answer: c) 2.37 x 10^-4

A solution of AgI contains 1.9 M Ag+. Ksp of AgI is 8.3 x 10-17. What is the maximum I- concentration that can exist in this solution?

a) 1.9 M
b) 4.4x10^-17 M
c) 8.3x10^-17 M
d) 1.6x10^-16 M

Answer: b) 4.4x10^-17 M

CaSO4 has a Ksp = 3x10-5. In which of the following would CaSO4 be the most soluble?

a) 1.0 M CaCl2(aq)
b) 0.5 M K2SO4(aq)
c) pure water
d) CaSO4 would have the same solubility in all three of these solutions

Answer: c) pure water

Determine if a precipitate will form when 0.96g Na2CO3 is combined with 0.2g BaBr2 in a 10L solution. (For BaCO3, Ksp = 2.8x10-9).

a) BaCO3 does not precipitate
b) BaBr2 will remain in solid form as it is insoluble in water.
c) It is impossible to know if any BaCO3 will precipitate with the information given.
d) BaCO3 precipitates

Answer: d) BaCO3 precipitates

A hypothetical compound MX3 has a molar solubility of 0.00562 M. What is the value of Ksp for MX3?

a) 2.69 x 10^-8
b) 9.48 x 10^-5
c) 3.16 x 10^-5
d) 2.99 x 10^-9

Answer: a) 2.69 x 10^-8

Rank the following salts from least to most molar solubility:

BiI Ksp = 7.7x10-19

Cd3(AsO4)2 Ksp = 2.2x10-33

AlPO4 Ksp = 9.8x10-21

CaSO4 Ksp = 4.9x10-5

a)Cd3(AsO4)2 < BiI < AlPO4 < CaSO4
b) AlPO4 < BiI < Cd3(AsO4)2 < CaSO4
c) Cd3(AsO4)2 < AlPO4 < BiI < CaSO4
d) CaSO4 < BiI < AlPO4 < Cd3(AsO4)2

Answer: b) AlPO4 < BiI < Cd3(AsO4)2 < CaSO4

Determine the molar solubility of some salt with the generic formula AB2 if Ksp = 2.56x102.

a) 1 M
b) 4 M
c) 0.1 M
d) 10 M

Answer: b) 4 M

The value of Ksp for SrSO4 is 2.8x10-7. What is the solubility of SrSO4 in moles per liter?

a) 5.3 x 10^-4
b) 1.4 x 10^-7
c) 2.8 x 10^-7
d) 7.6 x 10^-7

Answer: a) 5.3 x 10^-4

A hypothetical ionic substance T3U2 ionizes to form T2+ and U3- ions. The solubility of T3U2 is 4.04x10-20 mol/L. What is the value of the solubility-product constant?

a) 1.08x10^-97
b) 1.16 x 10^-95
c) 1.63x10^-39
d) 9.79x10^-39

Answer: b) 1.16 x 10^-95

Pure water is saturated with PbCl2. In this saturated solution, which of the following is true?

a) Ksp = [Pb2+]2[Cl-]
b) [Pb2+] = [Cl-]
c) Ksp = [Pb2+][Cl-]
d) [Pb2+] = 0.5[Cl-]

Answer: d) [Pb2+] = 0.5[Cl-]

The Ksp eqution for sodium bicarbonate (NaHCO3) should be written as:

a) Ksp = [NaH2+][CO32-]
b) Ksp = [Na+][H+][CO32-]
c) Ksp = [Na+][H+][C4+][O2-]3
d) Ksp = [Na+][HCO3-]

Answer: b) Ksp = [Na+][H+][CO32-]

Molar solubility is

a) the total molarity of the solution.
b) equal to the Ksp.
c) the number of moles that dissolve to give one liter of super-saturated solution.
d) the number of moles that dissolve to give one liter of saturated solution.

Answer: d) the number of moles that dissolve to give one liter of saturated solution.

What ions are present in solution after aqueous solutions of Cu(NO3)2 and K2S are mixed? Assume we mixed stoichiometric equivalent amounts of both reactants and 100% reaction.

a) Cu2+, NO3-, K+, S2-
b) Cu2+, S2-
c) No ions are present as both products form precipitates.
d) K+, NO3-

Answer: d) K+, NO3-

What is the net ionic equation for the reaction between aqueous solutions of Na3PO4 and CuSO4?

a) 3Cu2+ + 2PO43- --> Cu3(PO4)2
b) 2Na+ + SO42- --> Na2SO4
c) Cu2+ + PO43- --> CuPO4
d) No reaction occurs since no precipitate is formed.

Answer: a) 3Cu2+ + 2PO43- --> Cu3(PO4)2

Red blood cells contain Na+ ions, K+ ions, and water. If we place some red blood cells into a beaker full of pure water, what will happen to them?

a) they will wiggle around rapidly
b) they will swell and burst
c) nothing
d) they will shrivel and collapse

Answer: b) they will swell and burst

Which of the following statements is TRUE?

a) There is no net flow of H2O molecules from one solution to another.
b) There is a net flow of Cl- ions from solution B to solution A.
c) There is a net flow of H2O molecules from solution A to solution B.
d) There is a net flow of H2O molecules from solution B to solution A.

Answer: c) There is a net flow of H2O molecules from solution A to solution B.

Catalase (a liver enzyme) dissolves in water. A 14mL solution containing 0.166g of catalase exhibits an osmotic pressure of 1.2 Torr at 20°C. What is the molar mass of catalase?

a) 2.81x10^5 g/mol
b) 1.81x10^5 g/mol
c) 1.49x10^5 g/mol
d) 1.69x10^5 g/mol

Answer: b) 1.81x10^5 g/mol

A semi-permeable membrane can withstand an osmotic pressure of 0.75 atm. What molarity of aqueous magnesium bromide solution would reach the limit for this membrane? (Assume RT = 25 L·atm·mol-1)

a) 0.01 M
b) 0.01 mM
c) 0.03 mM
d) 0.03 M

Answer: a) 0.01 M

Rank the following aqueous solutions from lowest to highest boiling point: 0.5 m NaCl, 1 m KCl, 0.5 m BaCl2, and 1 m Ba(NO3)2. All salt are dissolved in water.

a) 1 m Ba(NO3)2 < 0.5 m NaCl < 0.5 m BaCl2 < 1 m KCl
b) 1 m KCl < 1 m Ba(NO3)2 < 0.5 m NaCl < 0.5 m BaCl2
c) 0.5 m BaCl2 < 1 m KCl < 1 m Ba(NO3)2 < 0.5 m NaCl
d) 0.5 m NaCl < 0.5 m BaCl2 < 1 m KCl < 1 m Ba(NO3)2

Answer: d) 0.5 m NaCl < 0.5 m BaCl2 < 1 m KCl < 1 m Ba(NO3)2

Calculate the vapor pressure at 20°C of a solution containing 0.61g of naphthalene in 16g of chloroform (CHCl3). Naphthalene (C10H8) has a low vapor pressure and may be assumed to be nonvolatile. The vapor pressure of chloroform at 20°C is 156 torr.

a) The vapor pressure would not change as naphthalene is considered non-volatile.
b) 28.10 torr
c) 20.90 torr
d) 150.65 torr

Answer: d) 150.65 torr

What will be the freezing point of a solution of 8 moles of sodium dichromate (Na2Cr2O7) dissolved in 16 kg of water? Use the following values:

Kb = 0.512 K/m

Kf = 1.86 K/m

a) 270.2 K
b) 272.2 K
c) 2.8°C
d) 275.8 K

Answer: a) 270.2 K

The freezing point of seawater is about -1.85°C. If seawater is an aqueous solution of sodium chloride, calculate the molality of seawater. The kf for water is 1.86 K/m.

a) 0.995 m
b) 0.497 m
c) 1.99 m
d) -0.497 m

Answer: b) 0.497 m

Theoretically, it should be harder to dissolve ( NaCl / Al2S3 ) in water because the (higher / lower) the charge density of a substance, the lower its solubility.

a) NaCl, lower
b) Al2S3, higher
c) Al2S3, lower
d) NaCl, higher

Answer: b) Al2S3, higher

How many moles of ions are contained in 1.27 L of a 1.75 M solution of Mg(NO3)2?

a) 0.741 mol
b) 6.67 mol
c) 4.45 mol
d) 2.22 mol

Answer: b) 6.67 mol

For solutions of a non-electrolyte, the van't Hoff factor is:

a) i = 3
b) i = 1
c) i = 2
d) i = 0

Answer: b) i = 1

In which of the following pairs do both compounds have a van't Hoff factor (i) of 2?

a) glucose and sodium chloride
b) perchloric acid and barium hydroxide
c) sodium sulfate and potassium chloride
d) sodium chloride and magnesium sulfate

Answer: d) sodium chloride and magnesium sulfate

Some distilled water is added to an empty beaker. A gram of copper (II) nitrate is added to the beaker and while the water is being stirred. After a few minutes, what is in the beaker?

a) solid copper, nitrate ions, and water
b) copper ions, nitrate ions, and water
c) nitrogen gas, copper atoms, electrons, and water
d) solid copper (II), nitrate, and water

Answer: b) copper ions, nitrate ions, and water

Which of the following would increase the solubility of a gas in water?

1. increase the temperature of the water

2. decrease the temperature of the water

3. increase the pressure of the gas above the water

a) 2 only
b) 1 only
c) 2 and 3
d) 1 and 3

Answer: c) 2 and 3

Which of the following is a possible combination of values for Hlattice and Hhydration respectively for a salt whose dissolution is endothermic?

a) -560, +560
b) +500, -520
c) +640, -620
d) -200, -304

Answer: c) +640, -620

Rank the following in terms of decreasing miscibility in C8H18 (octane), a major component of gasoline: C2H5Cl (chloroethane), H2O (water), C2H5F (fluoroethane), and C9H20 (nonane).

a) C2H5Cl > C2H5F > H2O > C9H20
b) H2O > C2H5F > C2H5Cl > C9H20
c) H2O > C9H20 > C2H5Cl > C2H5F
d) C9H20 > C2H5Cl > C2H5F > H2O

Answer: d) C9H20 > C2H5Cl > C2H5F > H2O

Both ammonia (NH3) and phosphine (PH3) are soluble in water. Which is least soluble and why?

a) ammonia because it does not form hydrogen bonds with water molecules
b) phosphine because the P-H bonds are so strong that they cannot break to enable phosphine to hydrogen-bond with water
c) phosphine because it does not form hydrogen bonds with water molecules
d) ammonia because the N-H bonds are so strong that they cannot break to enable the ammonia to hydrogen-bond with water

Answer: c) phosphine because it does not form hydrogen bonds with water molecules

are made when are dissolved in ____.

a) solutions, solvents, solutes
b) solutions, solutes, solvents
c) solvents, solutes, solutions
d) solutes, solutions, solvents

Answer: b) solutions, solutes, solvents

An unknown liquid has a vapor pressure of 88 mmHg at 45°C and 39 mmHg at 25°C. What is its heat of vaporization?

a) 2000 J/mol
b) 32,000 kJ/mol
c) 32 kJ/mol
d) 2000 kJ/mol

Answer: c) 32 kJ/mol

At 20°C the vapor pressure of dry ice is 56.5 atm. If 10g of dry ice (solid CO2) is placed in an evacuated 0.25 L chamber at a constant 20°C, will all of the solid sublime?

a) None of dry ice would sublime.
b) There is not enough information to answer this quesiton.
c) Yes.
d) Some of the dry ice will sublime, but not all of it.

Answer: c) Yes.

What is the vapor pressure of carbon disulfide at its normal boiling point?

a) Not enough informaiton.
b) 2.0 atm
c) 1.0 atm
d) 22.4 atm

Answer: c) 1.0 atm

Consider two empty containers A and B whose volumes are 10mL and 20mL respectively. 1mL of liquid water is put into each container and the temperature of each container is adjusted to 20°C. The gas pressure in container B, which still has some liquid water in it, is found to be 17 torr. How would the pressure in container A and the amount of liquid water in container A compare to that of container B?

a) the pressure would be the same, there would be an equal amount of liquid water
b) the pressure would be greater, there would be an equal amount of liquid water
c) the pressure would be greater, there would be less liquid water
d) the pressure would be the same, there would be more liquid water

Answer: d) the pressure would be the same, there would be more liquid water

In a closed vessel containing water, the pressure is 18 torr. If we add more water to the vessel, this equilibrium pressure would

All of these molecules are non-polar so their strongest IMF is dispersion forces. To rank their IMFs, remember that larger molecules exhibit stronger dispersion forces. Also, remember that vapor pressure is inversely proportional to IMF. So, to rank vapor pressure from smallest to largest, we simply rank the molecules from greatest IMFs to smallest IMFs.

In a closed vessel containing water, the pressure is 18 torr. If we add more water to the vessel, this equilibrium pressure would

a) change, but it is not possible to know if it will increase or decrease without more information.
b) decrease.
c) remain the same.
d) increase.

Answer: c) remain the same.

Rank the following liquids by vapor pressure from lowest to highest: C5H12, CH4, C3H8, C2H6, C4H10.

a) C5H12 < C4H10 < C3H8 < C2H6 < CH4
b) C2H6 < C3H8 < C4H10 < C5H12 < CH4
c) CH4 < C2H6 < C3H8 < C4H10 < C5H12
d) CH4 < C5H12 < C4H10 < C3H8 < C2H6

Answer: a) C5H12 < C4H10 < C3H8 < C2H6 < CH4

Which would have a higher vapor pressure: ethanol (C2H5OH) or dimethyl ether (CH3OCH3)?

a) dimethyl ether
b) They would have the same vapor pressure as their molecular weights are the same.
c) ethanol
d) It is impossible to tell unless the amount of each substance is known.

Answer: a) dimethyl ether

Which of the following would change the vapor pressure of a sample of water in a closed container?

1. decreasing the size of the container

2. lower the container temperature

3. removing water from the container

a) 2 and 3
b) 2 only
c) 1, 2, and 3
d) 1 and 2

Answer: b) 2 only

A sample of carbon dioxide is stored at 10,000 bar and 250K. This sample is then decompressed to 1 bar at constant temperature. Then, at constant pressure it is heated to 400K. Next, it is compressed at constant temperature to 200 bar. According to the phase diagram, how many phase transitions has the sample of carbon dioxide gone through, and what is its final state?

Use the phase diagram for CO2 in the question above to answer the following:

A sample of carbon dioxide is stored at 10,000 bar and 250K. This sample is then decompressed to 1 bar at constant temperature. Then, at constant pressure it is heated to 400K. Next, it is compressed at constant temperature to 200 bar. According to the phase diagram, how many phase transitions has the sample of carbon dioxide gone through, and what is its final state?

a) 3, liquid
b) 2, gas
c) 3, supercritical fluid
d) 2, supercritical fluid

Answer: d) 2, supercritical fluid

How much heat is required to heat 2 grams of ice at -30°C to steam at 100°C. Use the approximate values below for your calculations:

c{ice} = 2 J/g*C
dH{fusion} = 340 J/g
c{water} = 4 J/g*C
dH{vap} = 2260 J/g
c{steam} = 2 J/g*C

a) 6.00 kJ
b) 1.60 kJ
c) 6120 kJ
d) 6.12 kJ

Answer: d) 6.12 kJ

The ΔH°vap of methane is 8.519 kJ·mol-1 and its ΔS°vap is 85.58 J·mol-1·K-1. What is the boiling point of methane?

a) 0.09954°C
b) 99.54 K
c) 372.54 K
d) 0.09954 K

Answer: b) 99.54 K

What is the change in entropy ( Svap ) for the vaporization of ethanol ( Hvap = 38.6 kJ·mol-1 ) at its standard boiling temperature (78.4°C)?

a) 0.110 J·mol-1·K-1
b) 110 J·mol-1·K-1
c) 492 J·mol-1·K-1
d) 0.492 J·mol-1·K-1

Answer: b) 110 J·mol-1·K-1

Consider liquid ethane (CH3CH3) and liquid methanol (CH3OH). Which would you expect to have a larger H of vaporization?

a) It is impossible to tell unless you know the amount of each liquid involved.
b) Ethane, because it has stronger IMFs.
c) Methanol because it has a larger molar mass.
b) Methanol, because it has stronger IMFs.
d) Methanol, because it has stronger IMFs.

Answer: How large the dH of vaporization is of a substance is related to the strength of the IMFs involved, not the substance's mass nor how much of it is present. Methanol can perform hydrogen bonding (the strongest form of IMF) while ethane molecules are only held together by dispersion forces (the weakest form of IMF). Therefore, as the IMFs in methanol are greater, you would expect it to have a bigger dH of vaporization.

Which of the following statements is ALWAYS true about deposition?

a) None of the other answers are correct
b) dS > 0
c) dH < 0
d) dG < 0

Answer: c) dH < 0

Which of the phase changes below might have a H = 11.6 kJ·mol-1?

a) condensation
b) evaporation
c) deposition
d) freezing
b) evaporation

Answer: As dH is positive, the phase change must be an endothermic process (requiring the input of heat). Of the answer choices, only evaporation takes place when heat is added to the system. The others require the removal of heat.

Ice is heated at a constant pressure until it melts and vaporizes. What signs are associated with the total change in entropy and enthrall ( S and H ) for this sample of water?

a) dS = - , dH = -
b) dS = + , dH = -
c) dS = + , dH = +
d) dS = - , dH = +

Answer: c) dS = + , dH = +

How much NH3 is needed to react completely with 34g of CH3OH?

Consider the following reaction:

2NH3 + CH3OH --> products

How much NH3 is needed to react completely with 34g of CH3OH?

a) 36g NH3
b) 128g NH3
c) 9g NH3
d) 1.3g NH3

Answer: a) 36g NH3

Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems?

a) 45.0 moles of H2
b) 33.8 moles of H2
c) 15.0 moles of H2
d) No matter how many moles of H2 are added, 30.0 moles of NH3 cannot be produced.
d) No matter how many moles of H2 are added, 30.0 moles of NH3 cannot be produced.

Answer: 14.5 moles of N2 can only produce a maximum of 29.0 moles of NH3, regardless of how much H2 is added to the reaction.

14.5 moles N2 x (2 mol NH3/1 mol N2) = 29 mol NH3

A saturated solution of NaBr has a concentration of 45% NaBr in water. What is its solubility in water?

A)
82 g / 100 g H2O
B)
4.5 g / 100 g H2O
C)
55 g / 100 g H2O
D)
45 g / 100 g H2O

Answer: Not Available

Which of the following Solubility Product expressions below belongs to the following equilibrium reaction. Fe(OH)3(s) ←→Fe3+(aq) + 3OH-(aq)

Which of the following Solubility Product expressions below belongs to the following equilibrium reaction.
Fe(OH)3(s) ←→Fe3+(aq) + 3OH-(aq)

A) Ksp = [Fe3+] x 3 x [OH-]

B) Ksp =[Fe3+] x [OH−]3[Fe(OH)3]
C) Ksp = [Fe3+] x [OH-]

D) Ksp = [Fe3+] x [OH-]3

Answer D

A reaction is considered to be at equilibrium when the rate of the forward reaction is equal to rate of the reverse reaction.

Answer: TRUE

CaCO3 is considered insoluble in water. CaCO3(s) ↔ Ca2+(aq) + CO32-(aq) Which of the following is true about its equilibrium constant?

CaCO3 is considered insoluble in water.
CaCO3(s) ↔ Ca2+(aq) + CO32-(aq)
Which of the following is true about its equilibrium constant?

A) Kc = 1

B) Kc << 1

C) Kc >> 1

Answer B

What is the ionic equation for the dissolution of magnesium phosphate, Mg3(PO4)2?

A) Mg3(PO4)2(s) ←→Mg32+(aq) + (PO4)22-(aq)

B) Mg3(PO4)2(s) ←→Mg2+(aq) + PO43-(aq)

C) Mg3(PO4)2(s) ←→Mg3(PO4)2(aq)

D) Mg3(PO4)2(s) ←→3Mg2+(aq) + 2PO42-(aq)

Answer D

Consider the following reaction at equilibrium in a closed system: 2NO(g) + Cl2(g) ←→2NOCl(g) + heat What effect will introducing more Cl2(g) to the reaction vessel have on the equilibrium?

Consider the following reaction at equilibrium in a closed system:
2NO(g) + Cl2(g) ←→2NOCl(g) + heat
What effect will introducing more Cl2(g) to the reaction vessel have on the equilibrium?

A) The pressure of NO(g) will go down.

B) The pressure of NOCl(g) will go down.

C) The temperature will go down.

D) There will be no effect on the equilibrium.

Answer A

The fact that the process of forming a solution is non-spontaneous means that it absorbs heat.

Answer: True

For which of the reactions below does Kc (calculated using concentrations) equal KP (calculated using pressures)?

A) N2(g) + O2(g) ←→2NO(g) Kp = 0.050

B) 2NO(g) + Cl2(g) ←→2NOCl(g) Kc = 4.6 x 104

C) 2SO3(g)←→2SO2(g) + O2(g) Kp = 16.5

D) 2SO3(g)←→2SO2(g) +O2(g) Kc = 0.230

Answer A

Calculate the Reaction Quotient (Q) for AgCl when 500 mL of 4 x 10-5M AgNO3(aq) is mixed with 500 mL of 3 x 10-5M NaCl(aq) and determine whether AgCl will precipitate.

AgCl Solubility Product Ksp = 1.8 x 10-10

A) Q = 1.2 x 10-9; AgCl will not precipitate

B) Q = 1.2 x 10-9; AgCl will precipitate

C) Q = 3 x 10-10; AgCl will not precipitate

D) Q = 3 x 10-10; AgCl will precipitate

Answer A

METB is one of the compounds used as octane enhancers in unleaded gasoline. It is manufactured by the catalytic conversion of acetylene to benzene: 3C2H2(g) → C6H6(g). Which value of Kc would make this reaction most useful commercially?

A) Kc = 0.001

B) Kc = 1.00

C) Kc = 100

Answer C

Write the mathematical expression for the reaction quotient, Qc, for the following reaction:

2NH3(g) ←→N2(g) + 3H2(g)

A) Qc = (PN2 * P3H2) / (P3 NH3)

B) Qc = (PN2 * PH3) / PNH3

C) Qc = (P2 NH3) / (PN2 * P3 H2)

D) Qc = (PNH3) / (PN2 * PH2)

Answer A

Adding sodium cyanide to a saturated solution of AgCl(s) containing suspended AgCl will result in dissolving more AgCl since CN- forms a soluble complex with silver.

Answer: True

Which of the following actions will decrease the amount of hydrazine gas (N2H4) produced in a closed container in the following reaction? Check all correct answers that apply.

N2(g) + 2H2(g) ←→N2H4(g) + heat ΔH = 95 kJ

A) decrease the temperature of the reaction

B) increase the temperature of the reaction

C) remove N2 from the reaction

D) increase the pressure of the reaction by decreasing the volume of the closed container

Answers: B, C, D

A reaction is considered to be at equilibrium when the concentration of products equals the concentration of reactants.

Answer: False

For which of the reactions would a change in pressure not shift the equilibrium concentration?

A) N2(g) + O2(g) ←→2NO(g) Kp = 2 x 10-2

B) P4(g) + 5O2(g) ←→P4O10(s) Kc = 0.05

C) CH4(g) + 2O2(g) ←→CO2(g) Kp = 6 x 103

D) Br2(g)←→2Br(g) Kp = 9 x 10-15

Answer: A

Lewis acid-base adducts (products) can be charged complexes or uncharged solids.

Answer: TRUE!

If a reaction is reversible, when can it be said to have reached equilibrium?

Answer: When a system has reached equilibrium, no further changes in the reactant and product concentrations occur.

Assuming that no equilibria other than dissolution is involved, calculate the concentration of iodide ions, [I-(aq)], in the following saturated solution of lead iodide, PbI2(s).

Solubility product PbI2 Ksp = 9.8 x 10-9

A) [I-] = 0.0043M

B) [I-] = 9.8 x 10-9M

C) [I-] = 0.0013M

D) [I-] = 0.0026M

Answer D

According to LeChatelier's Principle which of the following will affect the equilibrium of the following reaction in a closed container? Check all correct answers that apply.

Heat + 2NH3(g) ←→3H2(g) + N2(g) ΔH = +1200 kJ

A) Add nitrogen gas

B)Add hydrogen gas

C) Add ammonia gas

D) Add argon gas

Answer: All the Above

For which of the reactions below does Kc (calculated using concentrations) equal KP (calculated using pressures)?

A)N2(g) + O2(g) ←→ 2NO(g) Kp = 2 x 10-2

B)P4(g) + 5O2(g) ←→P4O10(s) Kc = 0.05

C)CH4(g) + 2O2(g) ←→CO2(g) Kp = 6 x 103

D) Br2(g)←→2Br(g) Kp = 9 x 10-15

Answer A

For which of the reactions would a change in pressure not shift the equilibrium concentration?

A) N2(g) + O2(g)←→2NO(g) Kp = 0.050
B) 2NO(g) + Cl2(g) ←→2NOCl(g) Kc = 4.6 x 104
C) 2SO3(g)←→2SO2(g) + O2(g) Kp = 16.5
D) 2SO3(g)←→2SO2(g) +O2(g) Kc = 0.230

Answer A

Which of the following gases would be least soluble in water?

Answer: CH4

According to LeChatelier's Principle which of the following will not affect the equilibrium of the following reaction in a closed container? Check all correct answers that apply.

Heat + 2NH3(g)←→3H2(g) + N2(g) ΔH = +1200 kJ

Answer: Add argon gas to increase the pressure within the closed container.

Which of the following slightly soluble compounds has a solubility greater than that calculated from its solubility product because of hydrolysis of the anion present?

Answer: MgCO3