Enthalpy of Formation Worksheet
Explore the concept of enthalpy of formation and its application in chemical reactions for Grade 10 Chemistry students.
Includes
Standards
Topics
Enthalpy of Formation
Name:
Date:
Score:
Read each question carefully and provide the best possible answer. Show all your work for calculations.
1. Which of the following statements best defines the standard enthalpy of formation (ΔH°f)?
The enthalpy change when one mole of a compound is formed from its elements in their standard states.
The enthalpy change when a compound is dissolved in water.
The enthalpy change during any chemical reaction.
The energy required to break bonds in a compound.
2. For which of the following substances is the standard enthalpy of formation equal to zero?
CO2(g)
H2O(l)
O2(g)
NaCl(s)
3. The standard state for an element is its most stable form at temperature and pressure.
4. A reaction with a negative ΔH°f value is , meaning it releases heat.
5. Explain why the enthalpy of formation for an element in its standard state is zero.
6. The enthalpy of formation can be used to calculate the enthalpy change of a reaction using Hess's Law.
True
False
7. The formation of an ionic bond always releases energy.
True
False
8. Observe the diagram showing ionic bond formation. Briefly describe the process.
Match the term with its correct description.
9. Endothermic
a. Releases heat
10. Exothermic
b. Absorbs heat
11. Standard State
c. Most stable form at 25°C and 1 atm
12. Given the following standard enthalpies of formation:
ΔH°f [CO2(g)] = -393.5 kJ/mol
ΔH°f [H2O(l)] = -285.8 kJ/mol
ΔH°f [C3H8(g)] = -103.8 kJ/mol
Calculate the standard enthalpy change (ΔH°rxn) for the combustion of propane (C3H8) according to the balanced equation:
C3H8(g) + 5O2(g) → 3CO2(g) + 4H2O(l)