Practice Standard Enthalpy Of Formation (δhf0) (5.1) - Combustion and Fuels

Practice: Standard enthalpy of formation (ΔHf0)

Lesson 5.1Combustion and Fuels

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9 questions

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3 questions · about 2 min · pass mark 70%. Hints available.
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6 sample questions

Question 1.
Define standard enthalpy of formation (ΔHf0).
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Think about the energy change involved when making a compound.
Question 2.
Is ΔHf0 zero for elements under standard conditions?
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Consider how we refer to pure elements in enthalpy calculations.
3Question 3.
What is the value of ΔHf0 for elements in their standard states?
- 0
- 100 kJ/mol
- 50 kJ/mol
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Consider the basic definition of standard enthalpy.
4Question 4.
True or False: ΔHr can be directly calculated from the sum of standard enthalpies of formation.
- True
- False
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Reflect on the relationship of products and reactants' enthalpy.
Question 5.
A reaction involving 1 mole of CO2 being formed from C and O2 has ΔHf0 of -393.5 kJ/mol. Calculate the heat change associated with forming 2 moles of CO2.
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Consider how enthalpy changes with moles. What do you multiply by?
Question 6.
You have the following ΔHf0 values: C(s) = 0, O2(g) = 0, CO2(g) = -393.5 kJ/mol. Calculate ΔHr for the reaction: C(s) + O2(g) → CO2(g).
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Remember to apply the correct formula and where to pull values from.

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