CHI 201 ch 0

Question 1

What is the general form of a chemical reaction at equilibrium?

Answer 1

A + B -> <- C + D

Question 2

What is a characteristic of a reaction at equilibrium?

Answer 2

The reaction occurs in both directions at the same rate.

Question 3

What indicates a total reaction?

Answer 3

At least one reactant is in negligible quantity at the end of the reaction.

Question 4

What must be conserved when balancing a chemical reaction?

Answer 4

Conservation of matter and conservation of total charge.

Question 5

Provide an example of a balanced redox reaction.

Answer 5

2H2 + O2 -> 2 H2O

Question 6

Can negative stoichiometric coefficients be used in balancing reactions?

Answer 6

No, negative stoichiometric coefficients are not allowed.

Question 7

What does electroneutrality refer to in a dissolution example?

Answer 7

[H+] + [K+] = [HO-] + 2[SO42-]

Question 8

What is the definition of the activity of a compound i?

Answer 8

Ai = a dimensionless quantity characterizing the behavior of species i.

Question 9

How is activity defined for a solute?

Answer 9

ai = ϒi * [Ai]/ C0

Question 10

What is the activity of a dilute solution?

Answer 10

ϒi = 1

Question 11

How is activity calculated for a gas?

Answer 11

ai = Pi/P0

Question 12

What is the activity of a solid or solvent?

Answer 12

ai = 1

Question 13

What is the equilibrium constant expression?

Answer 13

K = [aC] * [aD] / [aA]* [aB]

Question 14

What does the equilibrium constant K depend on?

Answer 14

The reaction and temperature.

Question 15

What is the relationship between K and pK?

Answer 15

pK = -log10 K

Question 16

What happens to pK when K increases?

Answer 16

pK decreases.

Question 17

State Le Chatelier’s principle.

Answer 17

If a system is subjected to a disturbance, it will react to counteract that disturbance.

Question 18

What happens to the reaction when a reactant is added?

Answer 18

The reaction shifts to the right (towards products).

Question 19

What effect does increasing temperature have on an endothermic reaction?

Answer 19

The reaction shifts to the right.

Question 20

What effect does increasing pressure have on a reaction?

Answer 20

The reaction shifts towards the side with fewer moles of gas.

Question 21

What does a reaction progress table describe?

Answer 21

The evolution of quantities of substances from initial to final state.

Question 22

What information is found in the first line of the reaction progress table?

Answer 22

The balanced equation of the reaction.

Question 23

What information is found in the subsequent lines of the reaction progress table?

Answer 23

Initial quantity, quantity at time t, and quantity at equilibrium.

Question 24

What is a limiting reactant?

Answer 24

The reactant that is completely consumed first.

Question 25

How is the maximum advancement of a reaction determined?

Answer 25

It is the smallest value at which the quantity of one reactant becomes zero.