Homework Answers

PROBLEM: At 25°C (298 K), the reduction of copper(I) oxide is nonspontaneous AG = 8.9 kJ). Calculate the temperature at which the reaction becomes spontaneous. ΔΗ = 58.1 kJ AS = 0.165 kJ/K

PROBLEM: A key step in the production of sulfuric acid is the oxidation of S*O_{2}(g) to S*O_{3}(g) :

2S*O_{2}(g) + O_{2}(g) -> 2S*O_{3}(g)

At 298 K, Delta*G = - 141.6kJ; Delta*H = - 198.4kJ and Delta*S = - 187.9J / K

(a) Use the data to decide if this reaction is spontaneous at 25 degrees * C , and predict how Delta*G will change with increasing T.

(b) Assuming Delta*H and Delta*S are constant with increasing T, is the reaction spontaneous at 900.^ C ?

PROBLEM:

Choose the member with the higher entropy in each of the following pairs, and justify your choice [assume constant temperature, except in part (e)]:

(a) 1 mol of SO₂(g) or 1 mol of SO3(g)

(b) 1 mol of CO₂(s) or 1 mol of CO₂(g)

(c) 3 mol of O₂(g) or 2 mol of O3(g)

(d) 1 mol of KBr(s) or 1 mol of KBr(aq)

(e) seawater at 2°C or at 23°C

(f) 1 mol of CF4(g) or 1 mol of CCl4(g)

In this unbalaced chemical reaction.

Fe3O4 + H2O --------> Fe + H2O

How many grams of H2O will be produced, if 41.95g of Fe3O4 are reacted completely with hydrogen? Show the solution.

In the following unbalaced combustion reaction, how many grams of C8H18 will react with 4.77g of O2? Show the solution.

C8H18 + O2 -------> CO2 + H2O

How many grams of Fe2O3 will react with 18.97 grans of C in the REDOX reaction below? Show the solution

2Fe2O3 + 3C ------> 4Fe + 3CO2

In the chemical reaction below, how many grams of KCN will react with 81.55g of H2SO4? Show the solution.

2KCN + H2SO4 ------> K2SO4 + 2HCN

In the chemical reaction below, how many grams of HCl will be lrodiced by the reaction 2343.42g of CCl4? Show the solution.

CCl4 + 2HF -------> CCl2F2 + 2HCl

How many grams of NO will be produced, if 1.93g of H2O are also produced in the reaction below? Show the solution?

4NH3 + 5O2 -----> 4NO + 6H2O

How many grams of H2O are needed if 41.85g of O2 are to be produced from the reaction below? Show the solution

2K2O2 + 2H2O -----> 4KOH + O2