Enthalpy Stoichiometry Worksheet
Explore enthalpy changes in chemical reactions, apply Hess's Law, and calculate heats of reaction for Grade 10 Chemistry students.
Includes
Standards
Topics
Enthalpy Stoichiometry
Name:
Date:
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Read each question carefully and answer to the best of your ability. Show all your work for calculations.
1. Which of the following best describes an endothermic reaction?
A reaction that releases heat to the surroundings.
A reaction that absorbs heat from the surroundings.
A reaction that has no change in heat.
A reaction that only occurs at high temperatures.
2. What is the standard enthalpy of formation (ΔH°f) for an element in its most stable state?
Always positive
Always negative
Zero
Depends on the element
3. The energy required to break bonds is , while the energy released when forming bonds is .
4. Hess's Law states that the total enthalpy change for a reaction is the sum of the enthalpy changes for the individual .
5. Explain the difference between enthalpy and entropy.
6. A positive ΔH value indicates an exothermic reaction.
True
False
7. The enthalpy of formation of H₂O(l) is the same as H₂O(g).
True
False
8. Given the following reactions:
C(s) + O₂(g) → CO₂(g) ΔH = -393.5 kJ/mol
H₂(g) + ½ O₂(g) → H₂O(l) ΔH = -285.8 kJ/mol
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(l) ΔH = -890.3 kJ/mol
Calculate the enthalpy change for the reaction: C(s) + 2H₂(g) → CH₄(g)
9. A student performs an experiment to determine the heat of neutralization of a strong acid with a strong base using a calorimeter. The initial temperature of the solution was 22.5 °C and the final temperature after mixing was 29.8 °C. If the total volume of the solution was 100 mL and assuming the density and specific heat capacity are the same as water (1 g/mL and 4.18 J/g°C), calculate the heat absorbed by the solution.
