A silver block, initially at 58.5 °C, is submerged into 100.0 g of water at 24.8 °C, in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 26.2 °C. What is the mass of the silver block?

The term "alcohol" generally refers to the compound ethanol C₂H₅OH (or ethyl alcohol). The heat of vaporization for ethanol is 38.6 kJ/mol. If the combustion of ethanol is carried out in an adiabatic calorimeter, can its boiling point be measured? How much energy (in kJ units) is required to evaporate 15.4 g of ethanol at its boiling point from the liquid state to the gaseous state? The density of liquid ethanol is 0.790 g/mL.

Consider the following reaction wherein lead sulfide precipitates when a solution containing lead ions and sulfide ions is mixed:

Pb²⁺(aq) + S^2–(aq) → PbS(s)           ΔH = –131.8 kJ

(a) Determine the ΔH for the formation of 0.215 mol of PbS.

(b) Determine the ΔH for the formation of 3.50 g of PbS.

(c) Determine the ΔH when 3.65×10^–4 mol of PbS is dissolved in water.

Identify the elements in their standard states required for the formation equation of C₆H₁₂O₆(s) and write the balance reaction. Find the standard enthalpy of the formation using the standard table of values.

Write the formation equation used for calculating the enthalpy of formation of Fe₂O₃(s).

Which reaction refers to the formation of C₂H₅OH? 

a) C₂H₅OH(l) → 2 C(s) + 3 H₂(g) + 1/2 O₂(g)

b) 2 C(g) + 6 H(g) + O(g) → C₂H₅OH(l)

c) C₂H₅OH(l) → 2 C(l) + 6 H(l) + O(l)

d) 2 C(s) + 3 H₂(g) + 1/2 O₂(g) → C₂H₅OH(l)

Given the following reaction and standard enthalpy values, find ΔH°_f (kJ/mol) for cyclohexane (C₆H₁₂).

C₆H₁₂ (l) + 9 O₂ (g) → 6 CO₂ (g) + 6 H₂O (l)   ΔH°_Rxn = −3919.6 kJ

ΔH°_f (CO₂) = −393.5 kJ/mol

ΔH°_f (H₂O) = −285.8 kJ/mol

Acid spills are frequently neutralized using sodium carbonate or sodium hydrogen carbonate. The unbalanced equations that show the neutralization of benzoic acid are 

HCOOH(l) + Na₂CO₃(s) → NaHCOO(aq) + CO₂(g) + H₂O(l)

HCOOH(l) + NaHCO₃(s) → NaHCOO(aq) + CO₂(g) + H₂O(l)

Determine the amount of heat absorbed or released in kilojoules by the neutralization of 0.500 gallons of formic acid (density = 1.22 g/mL).

ΔH°_{f, NaHCOO(aq)} = −293.3 kJ/mol

ΔH°_{f, HCOOH(l)} = −425.0 kJ/mol

ΔH°_{f, Na2CO3} = −1130.7 kJ/mol

ΔH°_{f, NaHCO3} = −950.8 kJ/mol

ΔH°_{f, CO2(g)} = −393.5 kJ/mol

 ΔH°_{f, H2O(l)} = −285.8 kJ/mol

Wine on average has 11.6% alcohol by volume and a bottle (25.4 oz) contains 615 Calories on average. 

Calculate the percentage of Calories that come from alcohol in wine. 

Use the questions below to arrive at the answer.

(i) Write a balanced chemical equation for the reaction of ethanol, C₂H₅OH, with oxygen to make carbon dioxide and water.
(ii) Use enthalpies of formation to determine the enthalpy of reaction in part (i).
(iii) Calculate the mass of ethanol in an average bottle of wine if 11.6% of the total volume is ethanol and the density of ethanol is 0.789 g/mL.
(iv) Calculate the Calories released for the metabolism of ethanol
(v) Calculate the percentage of Calories that come from alcohol in wine. 

Determine the enthalpy of the reaction using Hess's law

2 Ag (s) + 1/2 O₂ (g) → Ag₂O (s) ΔH = -31.1 kJ/mol

Ag (s) + 1/2 Cl₂ (g) → AgCl (s) ΔH = -127.0 kJ/mol

H₂O (l) + Cl2 (g) → 2 HCl (aq) + 1/2 O₂ (g) ΔH = -48.6 kJ/mol

H₂ (g) + O₂ (g) → H₂O (l) ΔH = - 285.8 kJ/mol

Calculate ΔH°_rxn for the following reaction: 2 C(s) + H₂(g) → C₂H₂(g)

Use the given data below:

C₂H₂(g) + 5/2 O₂(g) → 2 CO₂(g) + H₂O(l)          ΔH° = −1299.5 kJ
C(s) + O₂(g) → CO₂(g)                                         ΔH° = −393.5 kJ
H₂(g) + 1/2 O₂(g) → H₂O(l)                                  ΔH° = −285.8 kJ

Given the following formation reactions and their enthalpies of formation

(reaction 1) 1/2 H₂ (g) + 1/2 Cl₂ (g) → HCl (g)                      ΔH = –92.3 kJ

(reaction 2) C (s) + 2 Cl₂ (g) → CCl₄ (g)                              ΔH = –95.7 kJ

(reaction 3) C (s) + 1/2 H₂ (g) + 3/2 Cl₂ (g) → CHCl₃ (g)     ΔH = –102.7 kJ

find ΔH for the reaction:

CHCl₃ (g) + Cl₂ (g) → HCl (g) + CCl₄ (g)