Download Thermochemistry 2 Matching Match each item with the correct

Thermochemistry 2
Matching
Match each item with the correct statement below.
a. heat of reaction
d. heat of fusion
b. heat of formation
e. heat of solution
c. Hess's law of heat summation
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1. the enthalpy change for a chemical reaction exactly as it is written
____
2. the enthalpy change caused by dissolving a substance
____
3. the energy required to melt a solid at its melting point
____
4. the change in enthalpy that accompanies the formation of a compound from its elements
____
5. states that if you add two or more thermochemical equations to give a final equation, you can also add the
heats of reaction to give the final heat of reaction
Multiple Choice
Identify the choice that best completes the statement or answers the question.
____
6. What does the symbol H stand for?
a. the specific heat of a substance
b. the heat capacity of a substance
c. the heat of reaction for a chemical reaction
d. one Calorie given off by a reaction
____
7. Standard conditions of temperature and pressure for a thermochemical equation are ____.
a. 0 C and 101 kPa
c. 0 C and 0 kPa
b. 25 C and 101 kPa
d. 25 C and 22.4 kPa
____
8. The amount of heat released by the complete burning of 1 mole of a substance is the ____.
a. specific heat
c. heat capacity
b. heat of combustion
d. heat of fusion
____
9. Calculate the energy required to produce 7.00 mol Cl O on the basis of the following balanced equation.
2Cl (g) + 7O (g) + 130 kcal
2Cl O (g)
a. 7.00 kcal
c. 130 kcal
b. 65 kcal
d. 455 kcal
____ 10. What is the standard heat of reaction for the following reaction?
Zn(s) + Cu (aq)
Zn (aq) + Cu(s)
( H for Cu = +64.4 kJ/mol; H for Zn = –152.4 kJ/mol)
a. 216.8 kJ released per mole
c. 88.0 kJ absorbed per mole
b. 88.0 kJ released per mole
d. 216.8 kJ absorbed per mole
____ 11. Calculate H for the following reaction.
C H (g) + H (g)
C H (g)
( H for C H (g) = 52.5 kJ/mol; H for C H (g) = –84.7 kJ/mol)
a. –137.2 kJ
c. 32.2 kJ
b. –32.2 kJ
d. 137.2 kJ
____ 12. Calculate the energy released when 24.8 g Na O reacts in the following reaction.
Na O(s) + 2HI(g)
2NaI(s) + H O(l)
H = –120.00 kcal
a. 0.207 kcal
c. 48.0 kcal
b. 2.42 kcal
d. 3.00 10 kcal
____ 13. Using a table that lists standard heats of formation, you can calculate the change in enthalpy for a given
chemical reaction. The change in enthalpy is equal to ____.
a.
H of products minus H of reactants
b. H of products plus H of reactants
c.
H of reactants minus H of products
d.
H of products divided by H of reactants
____ 14. The amount of heat involved in the synthesis of 1 mole of a compound from its elements, with all substances
in their standard states at 25 C, is called ____.
a. Enthalpy
c. standard heat of formation
b. heat of reaction
d. heat of solidification
____ 15. The symbol H stands for the ____.
a. specific heat of a substance
b. heat capacity of a substance
c. heat of reaction for a chemical reaction
d. standard heat of formation for a compound
H for the formation of rust (Fe O ) is –826 kJ/mol. How much energy is involved in the formation of 5
grams of rust?
a. 25.9 kJ
c. 66 kJ
b. 25.9 J
d. 66 J
Short Answer
17. What is the enthalpy change, ∆H in kJ, for the following reaction?
____ 16.
2Mg(s) + SiCl4(l) Si(s) + 2MgCl2(s)
Use the following:
Si(s) + 2Cl2(g)  SiCl4(l) ∆H = - 687 kJ
Mg(s) + Cl2(g) MgCl2(s) ∆H= - 641 kJ
18. What is the standard heat of reaction (∆H) for the combustion of ethane, C2H6 (g), to form carbon dioxide
gas and water? Write the final balanced equation for the reaction.
Standard heats of reaction:
C2H6 =84.68 kJ
O2 = 0.kJ
CO2(g) = 393.5 kJ
H2O(l) = -285.5 kJ
19. When 64.0 g of methanol (CH OH) is burned, 1454 kJ of energy is produced. What is the heat of combustion
for methanol?
20. Use the information below to calculate H for the following reaction.
2NO (g)  N O (g)
2N (g) + 2O (g)  2NO (g)
H = 67.7 kJ
N (g) + 2O (g)  N O (g)
H = 9.7 kJ