Question 1

When does a spontaneous reaction occur?

Accepted Answer

When delta G is negative. Moving towards the left

Question 2

When does a non-spontaneous reaction occur?

Accepted Answer

When delta G is positive. Moving towards the right.

Question 3

Define exergonic?

Accepted Answer

When delta G is negative (spontaneous) energy exiting the system.

Question 4

Define endergonic?

Accepted Answer

When delta G is positive (non-spontaneous). energy being added to the system.

Question 5

Define Exothermic

Accepted Answer

produces there own heat. Delta H(enthalpy) is negative in this instance.

Question 6

Define endothermic

Accepted Answer

Requires an input of energy. Delta H (enthalpy) is positive in this instance.

Question 7

What does Q represent?

Accepted Answer

The ratio of products to reactants

Question 8

What does Keq represent?

Accepted Answer

The reaction of products over reactants at equilibrium.

Question 9

Define equilibrium?

Accepted Answer

The point where the rate of the reaction in the FORWARD direction EQUALS the rate of the reaction in the REVERSE direction.

Question 10

How can you disturb equilibrium?

Accepted Answer

Removing or adding a product or reactant.

Question 11

If you remove a product or reactant from an equation will Q or Keq change?

Accepted Answer

Q will change because it is not at equilibrium.

Question 12

What direction will the reaction proceed in if a product or reactant is removed/added?

Accepted Answer

The direction necessary to re-establish equilibrium.

Question 13

When Keq is large, which has lower free energy: the products or the reactants?

Accepted Answer

A large Keq means there is more product than reactants because the product will have lower free energy than the reactants.

Question 14

Which way does equilibrium go towards/favors?

Accepted Answer

towards the lowest energy state because substances on the left are the weaker acids and bases.

Question 15

When Q is large, which has lower free energy: the products or reactants?

Accepted Answer

Q says nothing about the properties of the product or reactants.

Question 16

Which direction, forward or backward, will be favored in a reaction if delta G = 0?

Accepted Answer

Neither because you would be at equilibrium.

Question 17

Can a spontaneous reaction determine the rate of the reaction?

Accepted Answer

No, a spontaneous reaction does not determine the rate. Nonetheless spontaneous just means the reaction is favorable.

Question 18

Define chemical kinetics?

Accepted Answer

The study of reaction rates.

Question 19

Define transition state?

Accepted Answer

a state where there is instability and takes a great deal of energy to produce.

Question 20

Define activation energy (Ea)

Accepted Answer

the minimum energy required to cause a process (such as a chemical reaction) to occur.

Question 21

Define a catalyst?

Accepted Answer

Lowers the Ea  of a reaction by stabilizing the transition state, making its existence less thermodynamically unfavorable.

Question 22

Is a catalyst consumed in a reaction?

Accepted Answer

No, it is regenerated with each reaction cycle.

Question 23

Define enzymes (referring to activation energy)

Accepted Answer

Biological catalyst that increase the rate of a reaction by lowering the reaction's activation energy.

Question 24

Do enzymes affect delta G between reactants and products.

Accepted Answer

No they do not  because they have a kinetic role not thermodynamic.

Question 25

Will an enzyme alter the concentration of reagents at equilibrium?

Accepted Answer

No, it will only affect the rate at which the reactants and products reach equilibrium.

Question 26

define photosynthesis?

Accepted Answer

plants string energy from the sun in the bond energy of carbohydrates.

Question 27

define photoautotrophs?

Accepted Answer

things that use energy from light ("phot") to make their own ("auto") food.

Question 28

Define chemoheterotrophs?

Accepted Answer

using the energy of chemicals ("chemo") produced by other ("hetero") living things such as plants or animals.

Question 29

Define oxidation?

Accepted Answer

loss of electrons. 
LEO - Loss of electrons

Question 30

Define reduction?

Accepted Answer

Gain of electrons
GER - Gain of electrons.

Question 31

Define redox pair?

Accepted Answer

When one atom gets reduced another one must get oxidized

Question 32

Define catabolism?

Accepted Answer

The process of breaking down molecules.
cata - "breakdown"

Question 33

Define anabolism

Accepted Answer

Building up molecules.
ana - "break up"

Question 34

What is the function of ATP?

Accepted Answer

Store energy.

Question 35

What do we use the energy in ATP for?

Accepted Answer

Glycogen and fatty acids.

MCAT Biology review