Multiple Choice
The combustion of ethanol is shown below. C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(g) ΔH = –1367 kJ mol–1. The enthalpy change for the combustion of 12.5 g of ethanol is:
8. Thermochemistry
Thermochemical Equations
Back8. Thermochemistry
Thermochemical Equations
- Multiple Choice
Nitromethane (CH3NO2), sometimes used as a fuel for drag racing, burns according to the following reaction:
4 CH3NO2 (l) + 7 O2 (g) → 4 CO2 (g) + 6 H2O (g) + 4 NO2 (g) ∆Hº = – 2441.6 kJ
How much heat is released by burning 125.0 g of nitromethane (MW:61.044 g/mol)?
1views - Multiple ChoiceWhat is the approximate enthalpy change for the combustion of ethane in the reaction: 2 CH3-CH3(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(g)?
- Multiple ChoiceGiven the following thermochemical equation and data, calculate the standard enthalpy of formation (ΔH⁰f) for IF(g): IF7(g) + I2(g) → IF5(g) + 2 IF(g) with ΔH⁰rxn = -89 kJ. The standard enthalpies of formation are: IF7(g) = -941 kJ/mol, IF5(g) = -840 kJ/mol, I2(g) = 62.42 kJ/mol.
- Multiple ChoiceMothballs are composed primarily of the hydrocarbon naphthalene (C10H8). When 0.820 g of naphthalene burns in a bomb calorimeter, the temperature rises from 25.10 °C to 31.56 °C. If the heat capacity of the calorimeter is 5.11 kJ/°C, what is the ΔErxn for the combustion of naphthalene?
- Multiple ChoiceA 6.61 g sample of an unknown salt (MM = 116.82 g/mol) is dissolved in 150.00 g of water in a coffee cup calorimeter. Before placing the sample in the water, the temperature of the salt and water is 23.72 °C. After the salt has completely dissolved, the temperature of the solution is measured to be 20.15 °C. What is the enthalpy change (ΔH) for the dissolution of the salt in kJ/mol?
- Multiple Choice
The creation of liquid methanol is accomplished by the hydrogenation of carbon monoxide:
CO (g) + 2 H2 (g) → CH3OH (l) ∆Hº = – 128.1 kJ
How much heat (in kJ) is released when 125.0 g CO reacts with 2.32 x 102 g H2?
1views