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. Topic 9 – Kinetics and Equilibrium


4. Energy and Chemical reaction: Recalling concept facts and definitions

1. Exothermic chemical reactions
1) Absorbs heat energy 3) Absorbs electrons

2) Release heat energy 4) Release electrons

2. Which best describes all endothermic reactions?
1) They always release heat 3) They always occur spontaneously
2) They always absorb heat
4) They never occur spontaneously

3. In what type of reactions do the products of the reactions always have more energy than the
reactants?
1) Exothermic 3) Endothermic
2) Redox 4) Neutralization
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4. In which type of a reaction is the energy of reactants always greater than the energy of products?
1) Exothermic 3) Endothermic
2) Redox 4) Neutralization

5. Activation energy is need for reactions that are
1) Exothermic, only 3) Both exothermic and endothermic
2) Endothermic, only
4) Neither exothermic nor endothermic

6. In a chemical reaction, the difference between the potential energy of the products and the
potential energy of the reactants is called
1) Activation energy 3) Activated complex
2) Kinetic energy 4) Heat of reaction

7. The heat of reaction ( ∆H ) is equal to
1) Heat of products – Heat of reactants 3) Heat of products x Heat of reactants
2) Heat of products + Heat of reactants
4) Heat of products ÷ Heat of reactants

8. Which statement correctly describes heat of reaction for all endothermic reactions?
3) ∆H is negative because heat is released
1) ∆H is negative because heat is absorbed
2) ∆H is positive because heat is absorbed 4) ∆H is positive because heat is released

9. In exothermic reactions,
1) Heat is released, and ∆H is negative 3) Heat absorbed, and ∆H is negative
2) Heat is released, and ∆H is positive 4) Heat is absorbed, and ∆H is positive

10. ∆H (heat of reaction) of a chemical reaction is always equal to
1) Entropy of the products minus entropy of the reactants
2) Entropy of the reactant minus entropy of the products
3) Potential energy of the products minus the potential energy of the reactants
4) Potential energy of the reactant minus the potential energy of the products

11. In endothermic reactions,
1) The products have lower potential energy than the reactants, and ∆H is negative
2) The products have lower potential energy than the reactants, and ∆H is positive
3) The products have higher potential energy than the reactants, and ∆H is negative
4) The products have higher potential energy than the reactants, and ∆H is positive

12. Which correctly describes all exothermic chemical reactions?
1) ∆H is negative because the products have lower potential energy than the reactants

2) ∆H is positive because the products have lower potential energy than the reactants
3) ∆H is negative because products have higher potential energy than the reactants
4) ∆H is positive because the products have higher potential energy than the reactants

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