The following are solutions to chemistry questions. Identify the questions themselves.

Here are the solutions to the chemistry questions:

SECTION A (OBJECTIVE QUESTIONS)

1. Which compound contains covalent bonds? (D) Carbon tetrachloride
2. What happens to the oxidation number during reduction? (A) The oxidation number decreases.
3. Calculate the solubility in mol dm⁻³ of 40g of CuSO₄ dissolved in 100g of water at 120°C (Cu=64, S=32, O=16).
   • Molar mass of CuSO₄ = $64 + 32 + 4(16) = 160 \text{ g/mol}$
   • Moles of CuSO₄ = $\frac{40 \text{ g}}{160 \text{ g/mol}} = 0.25 \text{ mol}$
   • Volume of water = $100 \text{ g} \approx 100 \text{ mL} = 0.1 \text{ dm}^3$ (assuming density of water is $1 \text{ g/mL}$)
   • Solubility = $\frac{0.25 \text{ mol}}{0.1 \text{ dm}^3} = 2.50 \text{ mol/dm}^3$
   • The answer is (B) 2.50.
4. What is the empirical formula of a hydrocarbon containing 0.08 moles of carbon and 0.32 moles of hydrogen? (H=1, C=12, O=16)
   • Ratio of C:H = $0.08 : 0.32$
   • Divide by the smallest number (0.08): $\frac{0.08}{0.08} : \frac{0.32}{0.08} = 1 : 4$
   • The empirical formula is CH₄.
   • The answer is (D) CH₄.
5. The IUPAC system uses (D) Rule approach in naming compounds.
6. What is the oxidation number of Manganese in KMnO₄?
   • K is +1, O is -2. Let Mn be $x$.
   • $1 + x + 4(-2) = 0$
   • $1 + x - 8 = 0$
   • $x - 7 = 0 \implies x = +7$
   • The answer is (D) +7.
7. Boyle's law describes the relationship between (A) Pressure and volume of a gas.
8. Charles' law describes the relationship between (C) Temperature and volume of a gas.
9. The general gas equation combines which of the following laws? (B) Boyles, Charles and Avogadro's law.
10. The ideal gas equation is given by: (B) PV=nRT.
11. Graham's law of diffusion of a gas is inversely proportional to it's: (A) Square root of its molar mass.
12. Gay-Lussac's law relate the pressure and temperature of a gas at constant (C) Volume.
13. Avogadro's number represents the number of: (C) Atoms in one mole of a substance.
14. When solving a mass to mass stoichiometry problem, the molar mass of the: (D) Resistance and product are used to convert between grams and moles. (Assuming "Resistance" is a typo for "Reactant").
15. The equation $2H_2 + O_2 \rightarrow 2H_2O$ tell us that: (D) Two molecules of hydrogen react with one molecule of oxygen to form two molecules of water.

SECTION B (THEORY)

1a. Define the following terms: * (i) Empirical formula: The simplest whole-number ratio of atoms of each element in a compound. * (ii) Molecular formula: The actual number of atoms of each element present in a molecule of a compound.

**1b. A compound contains 31.91% potassium, 28.93