Standard Enthalpy of Combustion
Chemistry ⇒ Thermochemistry and Energetics
Standard Enthalpy of Combustion starts at 11 and continues till grade 12.
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A fuel has a standard enthalpy of combustion of -1500 kJ/mol. If 0.2 mol is burned, what is the energy released?
A hydrocarbon has a standard enthalpy of combustion of -2220 kJ/mol. If 44 g of the hydrocarbon is burned, how much energy is released? (Molar mass = 44 g/mol)
A student burns 0.5 g of ethanol (C2H5OH) and finds that it releases 13.6 kJ of energy. Calculate the enthalpy of combustion per mole of ethanol. (Molar mass of ethanol = 46 g/mol)
Calculate the energy released when 10 g of propane (C3H8) is burned. (Standard enthalpy of combustion of propane = -2220 kJ/mol, molar mass = 44 g/mol)
Calculate the enthalpy change when 2 moles of methane are completely combusted, given that the standard enthalpy of combustion of methane is -890 kJ/mol.
Calculate the mass of methane required to release 445 kJ of energy, given that the standard enthalpy of combustion of methane is -890 kJ/mol. (Molar mass = 16 g/mol)
Describe how Hess's Law can be used to determine the standard enthalpy of combustion of a substance.
Describe how the enthalpy of combustion of a liquid fuel can be determined experimentally in a school laboratory.
Describe the difference between enthalpy of combustion and enthalpy of formation.
Explain why the enthalpy of combustion of a fuel measured in the laboratory is usually less exothermic than the standard value.
Explain why the enthalpy of combustion of alkanes increases as the number of carbon atoms increases.
Explain why the standard enthalpy of combustion values are always negative.
Explain why water is written as a liquid in standard enthalpy of combustion equations.
State the standard conditions under which standard enthalpy of combustion is measured.
What is meant by the term 'standard enthalpy of combustion'?
Write the balanced chemical equation for the standard enthalpy of combustion of propane (C3H8).
A sample of a hydrocarbon is combusted in excess oxygen and produces 4.4 g of CO2 and 1.8 g of H2O. If the standard enthalpy of combustion of the hydrocarbon is –1560 kJ/mol, calculate the mass of hydrocarbon combusted and the energy released.
A student claims that the standard enthalpy of combustion of a substance can be positive if the reaction is carried out at a very high temperature. Is this statement correct? Justify your answer.
Explain, using bond enthalpies, why the enthalpy of combustion of methane is highly exothermic.
Given the following standard enthalpies of formation: ΔHf°(CO2(g)) = -393.5 kJ/mol, ΔHf°(H2O(l)) = -285.8 kJ/mol, ΔHf°(C2H6(g)) = -84.7 kJ/mol. Calculate the standard enthalpy of combustion of ethane (C2H6(g)).
