Practice Test Flashcards Preview

MCAT Chemistry > Practice Test > Flashcards

Flashcards in Practice Test Deck (16):
1

A hydrogen can only hydrogen bond if it is bonded to what atoms?

F, O, N only usually.

H's bonded to C do not participate in hydrogen bonding

2

If a dietary fat is not metabolized, how many calories do you consume from eating it?

0 calories because if you can't metabolize it then it doesn't provide any energy and therefore no calories

3

In order for a galvanic cell to undergo spontaneous reaction, what conditions need to be met?

negative G and a positive EMF (electromotive force)

4

How is detection time in mass spectroscopy determined?

The larger the mass, the longer the detection time (the force on the ion creates a smaller acceleration). Conversely, the greater the charge, the shorter the detection time (more attraction to the detector). Essentially, it is this mass/charge ratio that determines the detection time.

5

How do you increase the rate of an electrochemical cell?

Much like a catalyst increases the rate of a chemical reaction, increasing the movement of electrons, by increasing the current, will increase this rate of reaction.

6

What color is acid and base on Litmus paper?

Red = acid
Blue = base

7

What happens when the solubility product of a compound is exceeded?

At a given temperature, there is a point
where the maximum amount of compound has been dissolved in a given amount of solvent. This is referred to as the solubility of the compound, aka solubility product Ksp. When the maximum amount of dissolved solute has been reached, the solution is considered saturated. After reaching this saturation point, any additional solute will precipitate.

8

What is the heat of formation for N2 (g) and H2(g)?

Given that N2(g) and H2(g) are in their standard states, their heats of formation (ΔH°f) are zero.

9

Should you multiply electrode potentials by the number of moles when figuring out the electrode potential of a cell/reaction?

when dealing with half reactions, we do not multiply the electrode potentials by the number of moles; it is
a very common mistake to multiply the potential by some coefficient number.

10

What are the assumptions of ideal gas?

The main assumptions behind the ideal gas law are: molecules have zero volume, no intermolecular
forces exist, and each molecule undergoes a perfectly elastic collision with the walls of the container.

11

What is the connection between equilibrium constants and rates of reaction?

It is important to realize that we cannot make
any connection between equilibrium constants and rates of reaction—an equilibrium constant only indicate a
system’s behavior at its equilibrium status. Reaction rates can only be determined experimentally.

12

When is the pH of a buffer equal to the pKa of the acid?

When the acid and conjugate base concentrations are equal because pH = pKa + log[A-]/[HA]

13

How do you find pKa from Ka?

pKa = -log10(Ka)

ex. pKa = -log(10^7)
pKa = -7

14

When a small amount of strong base is added to a buffer, what happens to the pH of the solution?

There will be a slight increase in pH because of the strong base but it only increases by a small amount because of the good buffer solution.

15

The greater the vapor pressure, the faster or slower a compound evaporates?

Faster! So if a compound A has a vapor pressure of 50 and compound B has a vapor pressure of 20, at 25 degrees Celsius, compound A should have the greater rate of evaporation.

16

What kind of compound requires the least amount of oxygen in a combustion reaction? Like number of carbon and oxygen

The compound with the lowest carbon-to-oxygen ratio