Practice Hess's Law of Constant Heat Summation - 5.4.5 | 5. Thermodynamics | CBSE 11 Chemistry Part 1
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5.4.5 - Hess's Law of Constant Heat Summation

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Learning

Practice Questions

Test your understanding with targeted questions related to the topic.

Question 1

Easy

What does Hess's Law state?

💡 Hint: Remember, it's based on the initial and final states of a reaction.

Question 2

Easy

Define a state function.

💡 Hint: Temperature and pressure are examples of state functions.

Practice 4 more questions and get performance evaluation

Interactive Quizzes

Engage in quick quizzes to reinforce what you've learned and check your comprehension.

Question 1

What does Hess's Law state?

  • It is based on the mass of reactants
  • The total enthalpy change is equal to the total of the enthalpy changes for each path
  • It relates temperature to pressure

💡 Hint: Focus on what connects path and enthalpy.

Question 2

If a reaction A → B has a positive enthalpy change, what does it indicate?

  • True
  • False

💡 Hint: Think about whether the energy is gained or lost.

Solve 1 more question and get performance evaluation

Challenge Problems

Push your limits with challenges.

Question 1

Consider the following reaction steps: Step 1: C(graphite) + O2(g) → CO2(g) with dH = -393.5 kJ; Step 2: CO(g) + 1/2 O2(g) → CO2(g) with dH = -283 kJ. Given C(graphite) → CO(g) shows dH, calculate the enthalpy change for this step.

💡 Hint: Remember to rearrange the steps accordingly.

Question 2

Using Hess's law, predict the enthalpy change for the reaction where H2(g) + 1/2O2(g) → H2O(l) is known to release 285.8 kJ, and find the enthalpy of formation for H2O(l).

💡 Hint: Think about how combustion reactions relate to formation reactions.

Challenge and get performance evaluation