Multiple Choice Questions A sample of 3.00 moles of liquid

A sample of 3.00 moles of liquid water is heated from 10°C to 80°C. Determine q for this sample of water during this process. (The specific heat of water is 4.18 J/g°C.)
–878 J – wrong answer
878 J

18.1 kJ – wrong answer

–15.8 kJ
15.8 kJ
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8.00 grams of CH4 gas are completely combusted in the presence of excess oxygen gas in a bomb calorimeter. The heat capacity of the calorimeter and its contents is 18.2 kJ/°C, and the calorimeter rises in temperature from 25.0°C to 49.5°C. Determine the enthalpy of combustion of CH4 gas in units of kJ/mol.

–56 kJ/mol

–446 kJ/mol – wrong answer

446 kJ/mol – wrong answer

–892 kJ/mol
892 kJ/mol
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Gas grills typically use the combustion of propane, C3H8 (g), to heat up the grill. The combustion of propane is shown in the following balanced chemical reaction:
C3H8 (g) + 5 O2 (g) –> 3 CO2 (g) + 4 H2O (l)
Using the information given below, determine the ∆H° for this reaction.
Useful Information:
∆H°f (C3H8 (g)) = –104 kJ/mol
∆H°f (H2O (l) = –286 kJ/mol
∆H°f (CO2 (g) = –393 kJ/mol

–575 kJ/mol

–2219 kJ/mol – wrong answer

2219 kJ/mol

–2427 kJ/mol

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Consider the following chemical reaction and associated change in enthalpy:
H2 (g) + F2 (g) ––> 2 HF (g) ∆H = –542 kJ/mol
Determine ∆H for the following reaction:

HF (g) ––> 12 H2 (g) + 12 F2 (g) ∆H = ???

–271 kJ/mol

271 kJ/mol

–542 kJ/mol – wrong answer

542 kJ/mol

–1084 kJ/mol – wrong answer

1084 kJ/mol

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Consider the following data:

NO (g) + 1/2 O2 (g) –> NO2 (g) ∆H = –56 kJ/mol
N2O4 (g) –> 2 NO2 (g) ∆H = 58 kJ/mol
Determine the ∆H for the following reaction:
2 NO (g) + O2 (g) –> N2O4 (g)

∆H = –170 kJ/mol

∆H = –54 kJ/mol – wrong answer

∆H = 2 kJ/mol

∆H = 54 kJ/mol

∆H = 170 kJ/mol – wrong answer