For the reaction

$NaCl\left(s\right)\stackrel{water}{\to }N{a}^{+}\left(aq\right)+C{l}^{\text{–}}\left(aq\right),\Delta H=\text{+1 kcal/mol (+4.184 kJ/mol)}$

b. Does entropy increase or decrease in this process?

For the reaction 2 Hg(l) + O₂(g) → 2 HgO(s), ∆H = –43 kcal/mol (–180 kJ/mol).

a. Does entropy increase or decrease in this process? Explain.

For the reaction 2 Hg(l) + O₂(g) → 2 HgO(s), ∆H = –43 kcal/mol (–180 kJ/mol).

b. Under what conditions would you expect this process to be spontaneous?

The following reaction is used in the industrial synthesis of polyvinyl chloride (PVC) polymer:

Cl₂(g) + H₂C=CH₂(g) → ClCH₂CH₂Cl(l) ∆H = –52 kcal/mol (–218 kJ/mol)

a. Is ∆S positive or negative for this process?

Which reaction is faster, one with E_act = +10 kcal/mol(+41.8 kJ/mol) or one with E_act = +5 kcal/mol(+20.9 kJ/mol)? Explain.

Why does increasing concentration generally increase the rate of a reaction?

What is a catalyst, and what effect does it have on the activation energy of a reaction?

If a catalyst changes the activation energy of a forward reaction from 28.0 kcal/mol to 23.0 kcal/mol, what effect does it have on the reverse reaction?

For the reaction C(s, diamond) → C(s, graphite), ∆G = -0.693 kcal/mol (-2.90 kJ/mol) at 25 °C.

a. According to this information, do diamonds spontaneously turn into graphite?

The reaction between hydrogen gas and carbon to produce the gas known as ethylene is:

2 H₂(g) + 2 C(s) → H₂C=CH₂(g), ∆G = +16.3 kcal/mol (+68 kJ/mol) 25 °C.

a. Is this reaction spontaneous at 25 °C?

What is meant by the term 'chemical equilibrium'? Must amounts of reactants and products be equal at equilibrium?

Why do catalysts not alter the amounts of reactants and products present at equilibrium?

Write the equilibrium constant expressions for the following reactions:

a. 2 CO(g) + O₂(g) ⇌ 2 CO₂(g)

Write the equilibrium constant expressions for the following reactions.

d. C(s) + H₂O(g) ⇌ CO(g) + H₂(g)

Use your answer from Problem 7.53 to calculate the following:

a. [N₂O₄] at equilibrium when [NO₂] = 0.0250 mol/L

Use your answer from Problem 7.54 to calculate the following:

a. [O₂] at equilibrium when [CO₂] = 0.18 mol/L and [CO] = 0.0200 mol/L

Oxygen can be converted into ozone by the action of lightning or electric sparks:

3 O₂(g) ⇌ 2 O₃(g)

For this reaction, ∆H = +69kcal/mol (+285 kj/mol) and K = 2.68 × 10^-29 at 25 °C.

a. Is the reaction exothermic or endothermic?

Oxygen can be converted into ozone by the action of lightning or electric sparks:

3 O₂(g) ⇌ 2 O₃(g)

For this reaction, ∆H = +69kcal/mol (+285 kj/mol) and K = 2.68 × 10^-29 at 25 °C.

b. Are the reactants or the products favored at equilibrium?

Hydrogen chloride can be made from the reaction of chlorine and hydrogen:

Cl₂(g) + H₂(g) → 2 HCl(g)

For this reaction, K = 26 × 10³³ and ∆H = -44 kcal/mol(-184 kJ/mol) at 25 °C.

a. Is the reaction endothermic or exothermic?

When the following equilibria are disturbed by increasing the pressure, does the concentration of reaction products increase, decrease, or remain the same?

a. 2 CO₂(g) ⇌ 2 CO(g) + O₂(g)

For the following equilibria, use Le Châtelier's principle to predict the direction of the reaction when the pressure is increased by decreasing the volume of the equilibrium mixture.

a. C(s) + H₂O(g) ⇌ CO(g) + H₂(g)

The reaction CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g) has ∆H = -9.8 kcal/mol (-41 kJ/mol). Does the amount of H₂ in an equilibrium mixture increase or decrease when the temperature is decreased?

The reaction H₂(g) + I₂(g) ⇌ 2 HI(g) has ∆H = -2.2 kcal/mol (-9.2 kJ/mol). Will the equilibrium concentration of HI increase or decrease when

b. H2 is removed?

The reaction H₂(g) + I₂(g) ⇌ 2 HI(g) has ∆H = -2.2 kcal/mol (-9.2 kJ/mol). Will the equilibrium concentration of HI increase or decrease when

c. A catalyst is added?

The reaction Fe³⁺(aq) + Cl^-(aq) ⇌ FeCl²⁺(aq) is endothermic. How will the equilibrium concentration of FeCl²⁺ change when

b. Cl^- is precipitated by addition of AgNO₃?

For the unbalanced combustion reaction shown, 1 mol of ethanol, C₂H₅OH, releases 327 kcal (1370 kJ):

C₂H₅OH + O₂ → CO₂ + H₂O

e. If the density of ethanol is 0.789 g/mL, calculate the combustion energy of ethanol in kilocalories/milliliter and kilojoules/milliliter

For the production of ammonia from its elements, ∆H = -22 kcal/mol(-19 kJ/mol).

b. How much energy (in kilocalories and kilojoules) is involved in the production of 0.700 mol of NH₃?

Magnetite, an iron ore with formula Fe₃O₄, can be reduced by treatment with hydrogen to yield iron metal and water vapor.

a. Write the balanced equation.

Magnetite, an iron ore with formula Fe₃O₄, can be reduced by treatment with hydrogen to yield iron metal and water vapor.

d. This reaction has K = 2.3 × 10^-18. Are the reactants or the products favored?

For the evaporation of water, H₂O(l) → H₂O(g), at 100°C, ∆H = +9.72 kcal/mol (+40.7 kJ/mol).

b. How many kilojoules are released when 10.0 g of H₂O(g) is condensed?