📚 Part 1: Multiple Choice

Circle the letter of the best answer for each question.

1. Which type of reaction is represented by the equation: A + B → AB?

a) Decomposition

b) Synthesis (Combination)

c) Single displacement

d) Double displacement

2. What happens to the rate of reaction when temperature increases?

a) It decreases

b) It stays the same

c) It increases

d) It stops completely

3. In an exothermic reaction:

a) Energy is absorbed from the surroundings

b) Energy is released to the surroundings

c) No energy change occurs

d) The reaction cannot proceed

4. Which factors affect reaction rate? (Select all that apply)

Temperature

Concentration

Surface area

Catalysts

⚖️ Part 2: Balancing Chemical Equations

5. Balance the following chemical equations by writing the correct coefficients in the spaces provided:

a) _____ H₂ + _____ O₂ → _____ H₂O

b) _____ Na + _____ Cl₂ → _____ NaCl

c) _____ Mg + _____ HCl → _____ MgCl₂ + _____ H₂

6. Classify each of the balanced reactions above by writing the type of reaction (synthesis, decomposition, single displacement, or double displacement):

a) _________________________

b) _________________________

c) _________________________

✏️ Part 3: Short Answer and Calculations

7. Explain why increasing the surface area of a solid reactant increases the rate of reaction.

8. A student heats 50g of water from 20°C to 35°C during an exothermic reaction. Calculate the energy released by the reaction. (Specific heat capacity of water = 4.18 J/g°C)

Answer: _________________ J

9. Give one example each of:

a) An endothermic reaction: _________________________________

b) An exothermic reaction: __________________________________

10. Describe what a catalyst does and explain why it is useful in industrial processes.