Question

1. Which reaction(s) is/are exothermic? Select all that apply.

ΔH_f° in kJ/mol at 25°C

MgO	-601
Fe2O3(s)	-824
Ag2O (s)	-31
Al2O3(s)	-1676

Group of answer choices

a. 6Ag(s) + Fe2O3(s) --> 3Ag2O(s) + 2Fe(s)

b. 2Al(s) + Fe2O3(s) --> Al2O3(s) + 2Fe(s)

c. 3Mg(s) + Fe2O3(s) --> 3MgO(s) + 2Fe(s)

2. Which metal requires the most energy to extract (i.e. return to it's metallic form) from it's ore?

Reaction	ΔHf°     kJ/mol metal oxide
2Au(s) + 3/2 O2(g) --> Au2O3(s)	+131
2Ag(s) + 1/2 O2(g) --> Ag2O (s)	-31
Cu(s) + 1/2 O2(g) --> CuO(s)	-157
Pb(s) + 1/2 O2(g) --> PbO(s)	-217
Sn(s) + O2(g) --> SnO2(s)	-578
2Fe(s) + 3/2 O2(g) --> Fe2O3(s)	-824
2Al(s) + 3/2 O2(g) --> Al2O3(s)	-1676

Group of answer choices

a. aluminum

b. gold

c. lead

d. iron

3. Which of the following statements are true about making H₂O(g) from H₂O(l)? Select all that apply.

Group of answer choices

a. The process requires the transfer of +40.7 kJ/mol to the liquid water.

b. The process involves breaking covalent bonds O-H bonds. Therefore you can use bond energies to determine the heat of the reaction.

c. The number of intermolecular attractions between water molecules decreases in the process.

Answer 1

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