Physical Science Grade 12 Chemistry exam November 2024:

1. Which one of the following compounds has hydrogen bonds between its molecules?
   - A. CH₃CH₂CHO
   - B. CH₃COOCH₃
   - C. CH₃CH₂CH₂OH
   - D. CH₃COCH₃

2. Which one of the following is a correct general formula for carboxylic acids?
   - A. CₙH₂ₙ₊₁O₂
   - B. CₙH₂ₙO₂ₙ
   - C. CₙH₂ₙO₂
   - D. CₙHₙO₂

3. Study the reactions below:
   - Reaction 1: CH₃CH₂CHOHCH₃ → Compound P (major product) + H₂O
   - Reaction 2: Compound P → Compound Q
   - Which one of the following combinations is the correct IUPAC names of compounds P and Q?
     - A. But-1-ene and Butane
     - B. But-2-ene and Butane
     - C. But-1-ene and Butan-2-ol
     - D. But-2-ene and Butan-2-ol

4. The potential energy diagram below is for the following hypothetical chemical reaction. Which one of the following combinations of values for the heat of the reaction and the activation energies can be obtained for this reaction?
   - A. ΔH (forward) = -400 kJ/mol, Eₐ (forward) = 300 kJ/mol, Eₐ (reverse) = 100 kJ/mol
   - B. ΔH (forward) = -200 kJ/mol, Eₐ (forward) = 300 kJ/mol, Eₐ (reverse) = 100 kJ/mol
   - C. ΔH (forward) = -200 kJ/mol, Eₐ (forward) = 100 kJ/mol, Eₐ (reverse) = 300 kJ/mol
   - D. ΔH (forward) = -400 kJ/mol, Eₐ (forward) = 100 kJ/mol, Eₐ (reverse) = 300 kJ/mol

5. Initially, an equal number of moles of hydrogen gas (H₂) and iodine gas (I₂) are mixed in a closed container. The reaction reaches equilibrium at a constant temperature according to the balanced equation: H₂(g) + I₂(g) ⇌ 2HI(g). Which one of the following is always true at equilibrium?
   - A. [I₂] = [I₂]
   - B. [I₂] = 2[H₂]
   - C. [I₂] = [HI]
   - D. [H₂] = [HI]

6. Consider the following reaction at equilibrium: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g), ΔH = -188 kJ/mol. Which one of the changes to the reaction conditions below will increase the yield of SO₃(g)?
   - A. Increasing the temperature
   - B. Decreasing the temperature
   - C. Increasing the pressure
   - D. Decreasing the pressure

7. Which one of the following compounds is an example of an ester?
   - A. CH₃COOH
   - B. CH₃CH₂OH
   - C. CH₃COOCH₃
   - D. CH₃CH₂COOH

8. The reaction between ethanoic acid (CH₃COOH) and ethanol (CH₃CH₂OH) produces an ester and water. Write the balanced chemical equation for this reaction.

9. Calculate the pH of a 0.1 M solution of hydrochloric acid (HCl).

10. Explain the difference between a strong acid and a weak acid, providing examples of each.

These questions should give you a good mix of multiple-choice, calculation, and explanation-based queries to practice. Good luck with your studies!

 

 

 

 

 Here are the answers to the Physical Science Grade 12 Chemistry exam questions:

*Question 1*
1. C. CH₃CH₂CH₂OH

*Question 2*
2. A. CₙH₂ₙ₊₁O₂

*Question 3*
3. B. But-2-ene and Butane

*Question 4*
4. D. ΔH (forward) = -400 kJ/mol, Eₐ (forward) = 100 kJ/mol, Eₐ (reverse) = 300 kJ/mol

*Question 5*
5. D. [H₂] = [HI]

*Question 6*
6. B. Decreasing the temperature

*Question 7*
7. C. CH₃COOCH₃

*Question 8*
8. CH₃COOH + CH₃CH₂OH ⇌ CH₃COOCH₂CH₃ + H₂O

*Question 9*
9. pH = -log[H⁺] = -log(0.1) = 1

*Question 10*
10. A strong acid (e.g., HCl) completely dissociates in water, producing a high concentration of hydrogen ions. A weak acid (e.g., CH₃COOH) partially dissociates, producing a lower concentration of hydrogen ions.

Please note that these answers are provided for general guidance only. It's essential to consult your teacher or instructor for specific guidance and feedback on your performance.

 

 

 

 

 

 

 

 

 

 

 

 

 

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