Mastering Chemistry - Ch. 5

Calculate the standard enthalpy change for the reaction 2A+B⇌2C+2D

For the reaction given in Part A, how much heat is absorbed when 3.80 mol of A reacts?

How much heat is needed to raise the temperature of a 5.0 gram block of aluminum from 22.0° C to 37.0° C?

Combustion reactions are most conveniently studied _____.

The specific heat of silver (Ag) is 0.245 J/ºC g. Determine the energy required to raise the temperature of 350. g of Ag from 293 K to 400 K.

A total of 2.00 mol of a compound is allowed to react with water in a foam coffee cup and the reaction produces 173 g of solution. The reaction caused the temperature of the solution to rise from 21.00 to 24.70 ∘C. What is the enthalpy of this reaction? Assume that no heat is lost to the surroundings or to the coffee cup itself and that the specific heat of the solution is the same as that of pure water.

Which substance in the table undergoes the greatest temperature change when the same mass of each substance absorbs the same quantity of heat?

Is the process shown in the figure endothermic or exothermic?

It takes 54.0 J to raise the temperature of an 10.7 g piece of unknown metal from 13.0∘C to 24.3 ∘C. What is the specific heat for the metal?

The molar heat capacity of silver is 25.35 J/mol⋅∘C. How much energy would it take to raise the temperature of 10.7 g of silver by 12.1 ∘C?

What is the specific heat of silver?

What are the units of molar heat capacity?

What are the units of specific heat?

If you know the specific heat of copper, what additional information do you need to calculate the heat capacity of a particular piece of copper pipe?

A 100.0-g bar of gold is heated from 25 ∘C to 50 ∘C, during which it absorbs 322 J of heat. Assume the volume of the gold bar remains constant. Based on the data, calculate the specific heat of Au(s).

Suppose that the same amount of heat is added to two 10.0-g blocks of metal, both initially at the same temperature. One block is gold metal, and one is iron metal. Which block will have the greater rise in temperature after the addition of the heat? (Note that the specific heat of iron is 0.451 J/g⋅∘C.)

What is the molar heat capacity of Au(s)?

Calculate ΔH (in kJ/mol NaOH) for the solution process NaOH(s)→Na+(aq)+OH−(aq)Assume that the specific heat of the solution is the same as that of pure water.

Calculate ΔH (in kJ/mol NH4NO3) for the solution process NH4NO3(s)→NH+4(aq)+NO−3(aq) Assume that the specific heat of the solution is the same as that of pure water.

Is this process endothermic or exothermic?

A volume of 110. mL of H2O is initially at room temperature (22.00 ∘C). A chilled steel rod at 2.00 ∘C is placed in the water. If the final temperature of the system is 21.20 ∘C , what is the mass of the steel bar? Use the following values: specific heat of water = 4.18 J/(g⋅∘C) specific heat of steel = 0.452 J/(g⋅∘C)

The specific heat of water is 4.18 J/(g⋅∘C). Calculate the molar heat capacity of water.

A calorimeter contains 31.0 mL of water at 15.0 ∘C . When 2.00 g of X (a substance with a molar mass of 53.0 g/mol ) is added, it dissolves via the reaction X(s)+H2O(l)→X(aq) and the temperature of the solution increases to 26.5 ∘C . Calculate the enthalpy change, ΔH, for this reaction per mole of X. Assume that the specific heat of the resulting solution is equal to that of water [4.18 J/(g⋅∘C)], that density of water is 1.00 g/mL, and that no heat is lost to the calorimeter itself, nor to the surroundings.

Consider the reaction C12H22O11(s)+12O2(g)→12CO2(g)+11H2O(l) in which 10.0 g of sucrose, C12H22O11, was burned in a bomb calorimeter with a heat capacity of 7.50 kJ/∘C. The temperature increase inside the calorimeter was found to be 22.0 ∘C. Calculate the change in internal energy, ΔE, for this reaction per mole of sucrose.

Calculate the enthalpy of the reaction 2NO(g)+O2(g)→2NO2(g) given the following reactions and enthalpies of formation:

Calculate the enthalpy of the reaction 4B(s)+3O2(g)→2B2O3(s) given the following pertinent information:

The overall enthalpy change for a reaction _____.

Calculate ΔH for the reaction:NO (g) + O (g) → NO2 (g)given the following information:

Enthalpy diagram for combustion of 1 mol of methane. The enthalpy change of the one-step reaction equals the sum of the enthalpy changes of the reaction run in two steps: -890 kJ = -802 kJ+ (-88 kJ). What process corresponds to the -88 kJ enthalpy change?

Consider the following hypothetical reactions: A→BΔH=+24kJ B→CΔH=+62kJ Use Hess's law to calculate the enthalpy change for the reaction A→C.

Calculate the enthalpy change for the reaction P4O6(s)+2O2(g)→P4O10(s) given the following enthalpies of reaction: P4(s)+3O2(g)→P4O6(s)ΔH=−1640.1kJ P4(s)+5O2(g)→P4O10(s)ΔH=−2940.1kJ

From the enthalpies of reaction calculate ΔH for the reaction CO(g)+2H2(g) → CH3OH(g)

From the enthalpies of reaction calculate ΔH for the reaction of ethylene withF2:C2H4(g)+6F2(g)→2CF4(g)+4HF(g)

Given the following data: use Hess's law to calculate ΔH for the following reaction: N2O(g)+NO2(g)→3NO(g)

The equations given in the problem introduction can be added together to give the following reaction: overall: C + 1/2O2→CO However, one of them must be reversed. Which one?

What is the enthalpy for reaction 1 reversed? reaction 1 reversed: CO2→CO + 1/2O2

What is the enthalpy for the following reaction? overall: C + 1/2O2→CO

ΔH f° _____.

Given: C2H4(g)+3O2(g)↔2CO2(g)+2H2O(g) ΔHf(C2H4)=52.5kJ/mol ΔHf(H2O)=-285.8 kJ/mol Δ H0rxn=-1411.1 kJ/mol. Find ΔHf(CO2)=.

For which of the following reactions is ΔHrxn∘ equal to ΔHf∘ of the product(s)?You do not need to look up any values to answer this question.

The combustion of propane, C3H8C3H8, occurs via the reaction C3H8(g)+5O2(g)→3CO2(g)+4H2O(g)with heat of formation values given by the following table: SubstanceΔH∘fΔHf∘(kJ/mol)C3H8C3H8(g)-104.7 CO2(g)−393.5 H2O(g)−−241.8

Write a balanced chemical equation for the reaction depicted.

Predict whether w is positive, negative, or zero.

Using data from Appendix C in the textbook, determine ΔH for the formation of one mole of the product.

Choose the enthalpy diagram for the reaction. (Asume the bold arrow shows the reaction as written; combination of the two thin arrows shows an alternate route from A to B).

Suppose the overall reaction is endothermic. What can you conclude?

What is ΔH∘rxnΔHrxn∘ for the following chemical reaction? CO(g)+NH3(g)→HCN(g)+H2O(g) You can use the following table of standard heats of formation (ΔH∘f)(ΔHf∘) to calculate the enthalpy of the given reaction.