Chapter 15: Chemical Equilibrium

Question 1

Hemoglobin (Hb)

Answer 1

A protein found in re blood cells that reacts with O2.

Enhances the amount of O2 that can be carried through the blood stream.

Question 2

<=> “double arrow” meaning

Answer 2

dynamic equilibrium

Question 3

K, and its meaning for concentration

Answer 3

K = equilibrium constant

A large value of K indicates a high concentration of products at equilibrium.

Question 4

Concentration of O2 in the lungs and in the muscles

Answer 4

High, Low

Question 5

What happens to the reactants and products when a reaction starts

Answer 5

Reactants are consumed, concentrations decrease.

Products are made, concentrations increase.

Question 6

As reactant concentration decreases, the forward reaction rate …

Answer 6

decreases

Question 7

As product concentration increases, the reverse reaction rate…

Answer 7

increases

Question 8

what does it mean for a process to be reversible

Answer 8

Processes that proceed in both forward and reverse directions

Reactants <=> Products

Question 9

Single arrow vs. double arrow

-> , <=>

Answer 9

Single arrow indicates that all the reactant molecules are converted to product molecules at the end.

A double arrow indicates that the reaction is in equilibrium.

Question 10

Dynamic equilibrium definition, why it happens, and what happens to concentrations

Answer 10

the condition wherein the rates of the forward and reverse reactions are equal.

because the forward reaction slows and the reverse reaction accelerates, eventually they reach the same rate.

concentrations of all chemicals remain constant

Question 11

What does equilibrium NOT mean

Answer 11

The amounts of reactants and products are not equal.

the rates are equal but the concentrations can be different

Question 12

the position of equilibrium favors the products

Answer 12

equilibrium is reached only after all of the reactant molecules are consumed

Question 13

the position of equilibrium favors the reactants

Answer 13

equilibrium is reached only when a small percentage of the reactant molecules are consumed

Question 14

Law of mass action

Answer 14

the relationship between the chemical equation and the concentrations of reactants and products

aA + bB <=> cC + dD

Question 15

What doe the lowercase letters represent in

aA + bB <=> cC + dD

Answer 15

the lowercase letters represent the coefficients of the balanced chemical equation

Question 16

What is the K (equilibrium constant) formula

Answer 16

[C]^c[D]^d / [A]^a[B]^b

always products over reactants, no units

Question 17

Write the equilibrium constant, K, for the reaction

2 N2O5 (g) <=> 4 NO2 (g) + O2 (g)

Answer 17

[NO2]^4[O2] / [N2O5]^2

Question 18

what does the value of K imply when its value is greater than 1?

Answer 18

when the reaction reaches equilibrium there will be many more product molecules present than reactant molecules.

the position of equilibrium favors the products.

Question 19

what does the value of K imply when its value is less than 1?

Answer 19

when the reaction reaches equilibrium there will be many more reactant molecules present than product molecules.

the position of equilibrium favors the reactants.

Question 20

Value of K for forward and reverse reactions

Answer 20

K (forward) = 1/ K (reverse)

Question 21

What happens to K as the coefficients of an equation are multiplies by a factor

Answer 21

the equilibrium constant is raised to that factor

Question 22

What happens to K as you add equations to get a new equation

Answer 22

the equilibrium constant of the new equation is the product of the equilibrium constants of the old equations

Question 23

concentration of gas relation to partial pressure and how it relates to the equilibrium constant

Answer 23

the concentration of a gas in a mixture is proportional to its partial pressure

the equilibrium constant can be expressed as the ration of partial pressures of the gases

Question 23

concentration of gas relation to partial pressure and how it relates to the equilibrium constant

Answer 23

the concentration of a gas in a mixture is proportional to its partial pressure

the equilibrium constant can be expressed as the ration of partial pressures of the gases (in atm)

Question 24

partial pressure equilibrium constant using

[C]^c[D]^d / [A]^a[B]^b

Answer 24

[Pc]^c[Pc]^d / [Pa]^a[Pb]^b

Question 25

partial pressure units

Answer 25

atm

Question 26

are the values of Kp and Kc the same?

Answer 26

no necessarily because there is a difference in units

only the same when the change in n = 0 (c+d - (a+b))

Question 27

relationship between Kp and Kc

Answer 27

Kp = Kc (RT)^(change in n)

Question 28

what is change in n (for Kp and Kc

Answer 28

the difference between the number of moles of gaseous reactants and the number of moles of gaseous products

Question 29

Do the concentrations of pure solids and pure liquids change during the course of a reaction

Answer 29

no

Question 30

Write the equilibrium constant, K, for the reaction

CO2 (g) + H2O (l) <=> H+ (aq) + HCO3 - (aq)

Answer 30

[H+][HCO3-] / [CO2]

solids and liquids are not included in the equilibrium constant expression

Question 31

what is the most direct way of finding the equilibrium constant

Answer 31

measure the amounts of reactants and products in a mixture at equilibrium