Question

The enthalpy and entropy of fusion of ice at 0.00°C are 6.01 kJ/mol and 22.0 J/mol × K, respectively. What is the entropy change of the universe when one mole of ice melts in a large room maintained at 34.00°C? Assume the final temperature of the water is 0.00°C.

+19.6 J/K

–19.6 J/K

+2.4 J/K

–2.4 J/K

+41.5 J/K

What is the entropy change if 4.50 g of CaCO3(s) is placed in a container and allowed to decompose to CaO(s) and CO2(g) according to the following reaction?

CaCO3(s) D CaO(s) + CO2(g)

Substance

S° (J/mol × K)

CaCO3(s)

92.88

CaO(s)

39.75

CO2(g)

213.6

+7.22 J/K

–161 J/K

+35.7 J/K

+161 J/K

+3.57 J/K

What is the standard entropy change when 10.0 g of methane reacts with 10.0 g of oxygen to form carbon dioxide and liquid water?

Substance

S° (J/mol × K)

CH4(g)

186.2

O2(g)

205.0

H2O(mc076-1.jpg)

70.0

CO2(g)

213.6

–121 J/K

–37.9 J/K

–243 J/K

–154 J/K

–16.8 J/K

Determine the value of DG° for the reaction 2 NO2(g) D N2O4(g), given

Substance

D Hf°(kJ/mol)

S° (J/mol × K)

NO2(g)

33.2

240.0

N2O4(g)

9.2

304.2

–4.8 kJ

+4.8 kJ

+52.3 kJ

–52.3 kJ

–43.0 kJ

Determine DGrxn for C4H10(mc095-1.jpg ) + mc095-2.jpg O2(g) D 4 CO2(g) + 5 H2O(g) given the following.

Substance

D Gf°(kJ/mol)

C4H10(mc095-3.jpg )

–15.0

CO2(g)

–394.4

H2O(g)

–228.57

–2705.5 kJ/mol

–608.0 kJ/mol

–1791.0 kJ/mol

–2735.5 kJ/mol

+608.0 kJ/mol