Kinetics Quiz 20

Which change of phase is exothermic?

• H₂O_(s) ->H₂O_(g)

• NH_3(l) -> NH_3(g)

• H₂S_(g) -> H₂S_(l)

• CO_2(s) -> CO_2(l)

Consider the reaction: H₂O_(l) + energy -> H_2(g) + ½ O_2(g) Which of the following phrases best describes this reaction?

• endothermic, absorbing energy

• endothermic, releasing energy

• exothermic, absorbing energy

• exothermic, releasing energy

As the temperature of a system increases, the entropy of the system...

• decreases

• increases

• remains the same

Which series of physical change represents an entropy increase during each change?

• solid → liquid → gas

• gas → liquid → solid

• solid → gas → solid

• liquid → gas → solid

As products are formed in the following reaction, NH₄⁺_(aq) → NH₄Cl_(s) + 14.6kJ, the entropy of the system

• decreases and heat is absorbed

• increases and heat is released

• increases and heat is absorbed

• decreases and heat is released

As the number of effective collisions between the reactant particles in a chemical reaction decreases, the rate of the reaction

• remains the same

• increases

• decreases

Given the reaction:

A+B->C+D

The reaction will most likely occur at the greatest rate if A and B represent

• solutions of nonpolar molecular compounds

• ionic compounds in the solid phase

• nonpolar molecular compounds in the solid phase

• solutions of ionic compounds

Given the reaction:

Zn_(s) + 2HCl_(aq) --> Zn²⁺_(aq) + 2Cl^-_(aq) + H_2(g)

If the concentration of the HCl_(aq) is increased, the frequency of reacting collisions will

• decrease, producing a decrease in the reaction rate

• increase, producing an increase in the reaction rate

• increase, producing a decrease in the reaction rate

• decrease, producing an increase in the reaction rate

Raising the temperature speeds up the rate of a chemical reaction by increasing

• the effectiveness of the collisions, only

• neither the effectiveness nor the frequency of the collisions

• the frequency of the collisions, only

• both the effectiveness and the frequency of the collisions

Beaker A contains a 1-gram piece of zinc and beaker B contains 1 gram of powdered zinc. If 100 milliliters of 0.1 M HCl is added to each of the beakers, how does the rate of reaction in beaker A compare to the rate of reaction in beaker B?

• The rate in B is greater due to the smaller surface area of the zinc.

• The rate in A is greater due to the smaller surface area of the zinc.

• The rate in A is greater due to the larger surface area of the zinc.

• The rate in B is greater due to the larger surface area of the zinc.