Mcat Exam Missed Questions

Front 1

If the solution has pH=8 and an acid is add of pKa=7, what is the ratio of protonated to unprotonated acid?

Back 1

pH - pkA = 1
[A-]: [HA] = 10^1 : 1
so 10:1 will be deprotonated:protonated

Front 2

In a nearsighted person:
1. what can the person not focus on?
2. where does the image form?
3. What type of lens is needed?

Back 2

Distant objects

Before the retina (Inside the eye)

Diverging lens

Front 3

In a farsighted or presbyopia (can't contract muscle well)person:
1. what can the person not focus on?
2. where does the image form?
3. What type of lens is needed?

Back 3

Close objects

after the retina

Converging

Front 4

What kind of bond forms after dehydration of an alcohol?

What happens if you add Br2 and C(Cl)4 to the product?

Back 4

It will create an alkene

The C=C will cause the red color of bromine to disappear.

Front 5

Cyclohexane

Back 5

Cyclopropane

Cyclobutane

Cyclohexane

Cycloheptane

Front 6

What is the best way to separate two solutions with different polarities?

Back 6

Heat them very slowly, the H bonds will keep the more polar one in liquid phase.

Cooling column has no effect.

Front 7

What is the definition of codominant allele? Give example

Back 7

When a an allele is not dominant over another. Example is ABO blood type, both A and B are dominant over O, but the person produces both A and B antibodies, therefore they are codominant

Front 8

What is the definition of incomplete dominance? Give example

Back 8

When no allele is dominant over another, gives a dosage effect. Example is red and white snapdragons yield pink progeny.

Front 9

What is Epistasis?

Back 9

Epistasis is the term applied when one gene interferes with the expression of another.

Yield 9:7 progeny for 2 alleles versus 9:3:3:1

Front 10

Hydrogen goes from oxidation state +1 to 0 in H2

Back 10

Redox

Front 11

If a solution is 98% H2SO4 by weight, what is the % of HSO4- ions?

Back 11

[] of dirpotic acid

Front 12

1+1=2 second order rxn

remember that rate laws do not necessarily have their coefficients as exponential functions, must be determined experimentally unless given

Back 12

Rate Law

Front 13

+185 C

Back 13

Heat of Formation

Front 14

Lens

Back 14

1/3

Front 15

What is the definition of out of phase?

Back 15

When waves do not reach the same point at the same time, even if they are the same frequency and wavelength.
Like 2 runners running the same speed on the same track but at different starting points.

Front 16

When the MCAT says beta decay, which do they mean?

Back 16

B- decay

Front 17

What is the only decay in which the element doesn't change and why?

Back 17

Gamma decay, because the charge doesn't change. All other decays lose or gain a charge (-2 for alpha)

Front 18

As electroaffinity becomes more negative, what trend increases?

What trend becomes more negative?

Back 18

Electron ionization energy increases because if a atom is has a high affinity for electrons (more negative=more affinity), it will take increased energy to break e away

EA is the amount of energy liberated if an electron is added, so if it takes a lot of energy to pull an e away from F- (ionization energy), there is a large amount of energy liberated when that e is replaced (electron affinity)

Bottom line Ionization energy is inversely proportional to electron affinity.

Note also nobel gases have no EA because they are stable

Front 19

Fill in table

Back 19

VSPER

Front 20

Name all shape and geometry of 2 binding groups

Back 20

VSPER

Front 21

Name all shape and geometry of 3 binding groups

Back 21

Vsper

Front 22

Name all shape and geometry of 4 binding groups

Back 22

vsper

Front 23

Name all shape and geometry of 5 binding groups

Back 23

vsper

Front 24

Name all shape and geometry of 6 binding groups

Back 24

vsper

Front 25

When springs of equal K are on oppostite sides of a mass, what is the effective spring constant of the system

Back 25

2K

Springs on opposite sides can be summed

F=- K x +(-K)(-x)
=2Kx

Front 26

When is a solid body in translational equilibrium?

When is it in rotational equilibrium?

Back 26

A solid body is in translational equilibrium when the sum of its external forces = 0

A solid body is in rotational equilibrium when the sum of its external forces AND torques = 0

Front 27

How do you determine rate laws?

When can it be assumed?

Give general formula

What does it always involve and what does it usually involve?

Back 27

Rate law can only be determined experimentally unless it is an elementary reaction (either first order x=1 for monatomic rxn, or second order for biatomic reaction x+y=1+1=2)

Generally you use:
rate = k [A]^x [B]y


Usually only depends on reactants, but can include products.

Only uses molecules involved in rate determining step

Front 28

Give Arrhenius eqn.

What are 2 factors that will increase the rate of the rxn?

Back 28

From the second eqn:

Rxn rate can increase by
1. Adding catalyst to lower Ea
2. Increasing temp

Front 29

What are common strong bases?

Common weak bases?

Back 29

Common Strong Bases
Group I hydroxides LiOH or NaOH and metal amides NaNH2

Common weak bases
Group II hydroxides Ca(OH)2

Front 30

How do you calculate the pH of a strong acid?

Back 30

pH = - log [H+]

so [H+] = 10^(-pH)

Front 31

How do you determine pH of weak aci?

Back 31

For a weak acid you need to calculate the Ka by determining the ratio of dissociated ions

Set up eqn:
Ka = [H+][CN-] / [HCN]

Ka = X*X /.2-x

Assume x in .2-x is neglidible because it is a small amout
thus
Ka = x^2/.2

You will need other information to solve for x but this is the principle used

Front 32

What eqn is used for making for measure pH of a buffer solution of weak acid? How would the eqn change for a weak base?

Back 32

Henderson-Hasselbalch

For a base:

pOH = pKb + log [HA]/[A-]

Front 33

What is an assumption of buffer range?

Back 33

It's pH is +/- 1 of the pKa