# Chapter 18 Reaction Rates And Equilibrium Part 2 3/13/11

24 Questions | Total Attempts: 39  Settings  Chapter 18 Reaction Rates and Equilibrium Part 2 3/13/11

• 1.
Does entropy tend to increase or decrease in chemical reactions in which the total number of product molecules is greater than the total number of reactant molecules? ______________________
• A.

Entropy decreases

• B.

Entropy increases

• C.

Entropy stays the same

• 2.
Entropy tends to ______________________ when temperature increases.
• A.

Increase

• B.

Decrease

• C.

Stay the same

• 3.
What determines whether a reaction is spontaneous?
• A.

The size and direction of heat (enthalpy) changes and entropy changes together determine whether a reaction is spontaneous.

• B.

The size and direction of moisture(enthalpy) changes and entropy changes together determine whether a reaction is spontaneous.

• C.

The size and amount of heat (enthalpy) changes and entropy changes together determine whether a reaction is spontaneous.

• 4.
Why is an exothermic reaction accompanied by an increase in entropy considered a spontaneous reaction?
• A.

Because both factors are favorable too many

• B.

Because both factors are not favorable

• C.

Because both factors are favorable

• 5.
A nonspontaneous reaction, one in which the products are __________, has heat changes, entropy changes, or both working against it.
• A.

Not favored

• B.

Favored

• C.

Small

• 6.
What is the symbol for entropy and what are the units?
• A.

J; P/S

• B.

R; J/P

• C.

S; J/K

• 7.
The standard entropy of a liquid or solid substance at 25 °C is designated as ______________________ .
• A.

S exponent 0

• B.

S exponent 9

• C.

S exponent 4

• 8.
What is the pressure at S exponent 0 for gaseous substances?
• A.

101.9 kPa

• B.

101.3 kPa

• C.

101.6 kPa

• 9.
The theoretical entropy of a perfect crystal at 0 K is ____________.
• A.

-0

• B.

4

• C.

0

• 10.
What is the equation used to calculate standard entropy change (triangleS exponent 0)?
• A.

ΔS0 =S exponent 1 (products) - S exponent -1 (reactants)

• B.

ΔS0 =S exponent 0 (products) - S exponent -0 (reactants)

• C.

ΔS0 =S exponent 0 (products) - S exponent 0 (reactants)

• 11.
What is the standard entropy of calcium carbonate (CaCO3)?
• A.

98.7 J/Kmol

• B.

88.7 J/Kmol

• C.

108.7 J/Kmol

• 12.
The Gibbs free-energy change (ΔG) is the maximum amount of energy that can be coupled to another process to do useful
• A.

Work

• B.

Rest

• C.

Product

• 13.
What is the equation used to calculate the Gibbs free-energy change?
• A.

ΔG = ΔH =TΔS, where ΔH is the change in enthalpy, ΔS is the change in entropy, and temperature (T) is in kelvins.

• B.

ΔG = ΔH =TΔS, where ΔH is the no change in enthalpy, ΔS is the change in entropy, and temperature (T) is in kelvins.

• C.

ΔG = ΔH =TΔS, where ΔH is the small change in enthalpy, ΔS is the change in entropy, and temperature (T) is in kelvins.

• 14.
The numerical value of ΔG is _____________________ in spontaneous processes because the system loses free energy; the numerical value of ΔG is _____________________ in nonspontaneous processes because the system requires that work be expended to make them go forward at the specified conditions.
• A.

Negative, positive

• B.

Positive, negative

• C.

Both negative, positive and positive, negative

• 15.
What is the equation used to calculate the standard free-energy change (ΔG exponent 0) of a  chemical reaction?
• A.

ΔGexponent0 = ΔH exponent 0=TΔS0, where ΔH exponent 0 and ΔS exponent 0 are known, and the temperature (T) is in kelvins.

• B.

ΔG exponent 0 = ΔHexponent0=TΔSexponent 0, where ΔHexponent 0 and ΔSexponent 0 are unknown, and the temperature (T) is in kelvins.

• C.

ΔG exponent 0 = ΔH exponent 0=TΔS exponent 0, where ΔH exponent 0 and ΔS exponent 0 are known, and the temperature (T) is in kelvins.

• 16.
How do you calculate the standard free-energy change (ΔG exponent 0) of a chemical reaction when ΔH exponent 0 and ΔS exponent 0 are unknown?
• A.

You use ΔG exponent 0 f , the standard free-energy change for the formation of substances from their elements. The formula is ΔG0 = ΔG exponet 0 f (products) = ΔG exponent0 f (reactants).

• B.

You use ΔG exponent 0 f , the standard free-energy no change for the formation of substances from their elements. The formula is ΔG0 = ΔG exponet 0 f (products) = ΔG exponent0 f (reactants).

• C.

You use ΔG exponent 0 t , the standard free-energy no change for the formation of substances from their elements. The formula is ΔG0 = ΔG exponet 0 f (products) = ΔG exponent0 f (reactants).

• 17.
What is a one-step reaction?
• A.

It is a reaction with ore than one activated complex between the reactants and the products.

• B.

It is a reaction with only one activated complex between the reactants and the products.

• C.

It is a reaction with only one activated complex between the reactants and the heat.

• 18.
What is a specific rate constant (k) for a reaction?
• A.

The constant is a proportionality constant relating the concentrations of chemical change to the rate of the reaction.

• B.

The constant is a proportionality constant relating the concentrations of reactants to the rate of the reaction.

• C.

The constant is a proportionality constant relating the concentrations of product to the rate of the reaction.

• 19.
The ______________________ of a reaction is the power to which the concentration of a reactant must be raised to give the experimentally observed relationship between concentration and rate.
• A.

Product

• B.

Amount

• C.

Order

• 20.
In a first-order reaction, the reaction rate is directly proportional to the concentration of _______ .
• A.

Two or more reactants

• B.

Both reactants and products

• C.

Only one reactant

• 21.
How do you determine the actual kinetic order of a reaction?
• A.

The actual chemical order must be determined by experiment.

• B.

The actual kinetic order must be determined by experiment.

• C.

The actual potential order must be determined by experiment.

• 22.
What is a reaction progress curve?
• A.

A reaction progress curve is a graph of all the energy changes that occur as reactants are converted to products.

• B.

A reaction progress curve is a graph of all the energy changes that occur as products are converted to reactants.

• C.

A reaction progress curve is a graph of all the energy changes that occur as kentic energy is converted to products.

• 23.
A(n) ______________________ reaction is one in which reactants are converted to products in a single step.
• A.

Major

• B.

Elementary

• C.

Median

• 24.
What is an intermediate product of a reaction?
• A.

It is a product of a reaction that becomes a reactant of same reaction.

• B.

It is a reaction of a product that becomes a reactant of another reaction.

• C.

It is a product of a reaction that becomes a reactant of another reaction.

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