MCAT
Showing posts with label MCAT. Show all posts
Showing posts with label MCAT. Show all posts

What is the diff between average velocity and instantaneous velocity? Which is more important? Give the eq for each

What is the diff between average velocity and instantaneous velocity? Which is more important? Give the eq for each



Answer: Average velocity is the change in displacement over a period of time (delta x / delta t). Instantaneous velocity is the displacement for a specific moment in time so a specific time eg. t=5s will be given (delta x /t)

Write out the chart for common angles and their sin and cosines?

Write out the chart for common angles and their sin and cosines?



Answer:


Column 1 (Angles)= 0,30,45,60,90
Column 2 (Sines)= 0 over 2 (0), Square root 1 over 2 (0.5), Sq rt 2 over 2 (0.7), Sq rt 3 over 2 (0.9), Sq rt 4 over 2 (1.0)
Column 3 (Cosines) = Vice Versa

What are the 4 types of motion?

What are the 4 types of motion?



Answer: Translational, Rotational, Vibrational, Combination

What is the 5 point Verbal Strategy?

What is the 5 point Verbal Strategy?



Answer:

1) Know your author (you must answer questions from his/her point of view)
2) What is the main idea
3) Look at the answers for hints and use process of elimination
4) Look at the question for a hint
5) Then you may go back to the passage (last resort only!)

How many bonds will carbon, nitrogen, oxygen an hydrogen form and why?

How many bonds will carbon, nitrogen, oxygen an hydrogen form and why?



Answer: Since they have 4, 5, 6, 1 valence electrons and therefore need 4, 3, 2, 1 to reach their octets, the will form 4,3,2,1 bonds...The 1,2,3,4 rule! Any deviations must mean the atoms carry a charge (due to a loss or gain of electrons)

What is meant by hybridization. Use carbon as an example to explain.

What is meant by hybridization. Use carbon as an example to explain.



Answer: The bringing of orbitals together to form a new type of orbital. This has to happen around an atom before it can bond with another atom. All atoms have different types of orbitals for their bonding (valence) electrons eg. Carbon has 1 in the s and 3 in the p (total 4). The s will have a different energy level from the p's and this is NOT OK to allow carbon to bond (all electrons must have same energy level). So by rearrangings (hybridizing) its orbital, carbon forms 4 sp3 ones which will have the same level of energy and thus allow it to bond with other atoms.

What are sigma and pi bonds?

What are sigma and pi bonds?



Answer: The two types of covalent bonds. Sigma--the electron density is shared between the two nuclei. Pi---the elec den is above and below the internuclear region (the second bond of a double bond or second plus third of a triple bond)


Describe the 3 types of major bonds and give examples?

Describe the 3 types of major bonds and give examples?



Covalent--an even sharing due to same elec negativities eg. C-C
Ionic--a transfer of electrons from a less en atom to a more en atom eg Li-F. Ionic bonds are bonds between two opp charged atoms. They are stronger than cov bonds but more easily solvated than cov when in polar solvents (

What the types of 4 structures important on the MCAT?

What the types of 4 structures important on the MCAT?



Answer:


  1. Lewis Dot Structures--A 2D depiction of molecules showing valence electrons (shared and unshared) as dots.
  2. Bond-Line formula---carbons depicted as line, func groups shown but no H's shown,
  3. Fischer Projections---vertical lines are going into the page, horizontal ones come out.
  4. Newman projections---a straight view down the axis on on of the single bonds, the intersecting lines and large circle are carbons.


What does the n, iso, sec and tert mean in naming organic compounds?

What does the n, iso, sec and tert mean in naming organic compounds?



Answer: This method is used to name branched hydrocarbon substituents (not a main chains). If the substituent is a "normal" straight chain it is n eg. n-butyl. However drop the n and name as a butyl group. If the substituent branches into TWO METHYL groups AT THE END of it, then it is an iso eg. isobutyl. It is sec if the carbon connected to the parent is connected to two carbons (but does not form two methyl groups). Tert is if connected to three. Sometimes tert is abbreviated to t. For example
5 t-butyl

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