*WAEC GCE CHEMISTRY THEORY* (2ai) - The volume of gas molecules is negligible compared to the volume of the container. - Collisions between gas molecules are perfectly elastic (no energy loss). (aii) Mass of gas = 0.8 g Volume = 560 cm3 = 0.560 dm3 Temperature (T) = 0 °C = 273 K Pressure (P) = 1 atm = 101325 N/m2 Gas constant (R) = 8.31 J K-1 mol-1 PV = nRT n = PV / RT n = (101325 N/m2 × 0.560 × 10-3 m3) / (8.31 J K-1 mol-1 × 273 K) n = 56.742 / 2268.63 = 0.025 mol Molar mass = Mass / Moles = 0.8 g / 0.025 mol = 32 g/mol (2b) - Ionization energy increases across a period. - Oxygen has a lower ionization energy than nitrogen because, Oxygen has 4 electrons in the 2p orbital, while nitrogen has 3. The extra electron in oxygen causes repulsion, making it easier to remove. Nitrogen has a half-filled 2p orbital, which is more stable and requires more energy to remove an electron. (2c) - HOCl is acidic: It can donate a proton (H+) in solution, forming OCl-. The presence of the electronegative chlorine atom makes the O-H bond more polar, facilitating proton donation. - NaOH is basic: It dissociates in water to form Na+ and OH- ions. The OH- ions make the solution basic by accepting protons (H+).