GEN CHEM 2 QUARTER 2 1ST SUMMATIVE TEST

Which of the following is an example of a spontaneous process?

• Rusting of iron

• Reassembling of broken glass

• Conversion of water to hydrogen and oxygen gas

• None of the above

What will happen in the entropy if the phase changes from liquid to solid is considered?

• decrease

• increase

• stays the same

• cannot be determined

Which of the following statements is correct?

• Spontaneous processes are always fast.

• The spontaneity of a process depends on temperature.

• Only exothermic processes can take place spontaneously.

• All spontaneous processes could be classified as a reversible reaction.

Which of the following is NOT true about entropy?

• It is denoted by a symbol S.

• It is a measure of the randomness or disorder of a system.

• It is a measure of how much energy is unavailable for conversion into work.

• A positive value of a change in entropy indicates that the final state is less random than the initial state.

Calculate the entropy change (ΔS^o) for the following reaction at 25^oC;

2SO_2(g) + O_2(g) --> 2SO_3(g)

Given the following standard entropy values at 25^oC

SO_2(g) – 248.5 J/K-mol;

O_2(g) – 205.0 J/K-mol;

SO_3(g) – 256.2 J/K-mol

• 7.7 J/K

• -15.4 J/K

• -87 J/K

• -189.6 J/K

At constant temperature and pressure, which of the following is TRUE about the relationship of the sign ΔG and spontaneity?

• ΔG=0, the reaction is at equilibrium.

• ΔG=0, the reaction is nonspontaneous.

• ΔG>0, the reaction is spontaneous in the forward direction

• ΔG<0, nonspontaneous in the forward direction

Of the following, the entropy of gaseous _________ is the largest at 25^oC and 1 atm.

• CH₄

• C₂H₂

• C₂H₄

• C₂H₆

Given the following table of thermodynamic data,

Complete the sentence. The vaporization of TiCl₄ is _____________.

• spontaneous at all temperatures

• nonspontaneous at all temperatures

• spontaneous at low temperatures and nonspontaneous at high temperature

• nonspontaneous at low temperatures and spontaneous at high temperature

Consider the reaction: Ag⁺_(aq) + Cl^-_(aq) --> AgCl_(s)

Given the following table of thermodynamic data,

determine the temperature (in degrees Celsius) above which the reaction is nonspontaneous under standard conditions.

• 150.5

• 432.8

• 1235

• 1641

The entropy of the universe always increases when ____________________.

• ΔS is > 0

• ΔH is < 0

• ΔS is > 0 and ΔH is < 0

• ΔS is < 0 and ΔH is > 0