WAEC Chemistry Past Questions & Answers - Page 6

Dalton's atomic theory cannot be explained by the application of the kinetic theory of gases because it deals with the atomic-level structure and behavior of matter, which is beyond the scope of the kinetic theory's focus on the macroscopic behavior of gas particles. The other laws (Charles' law, Gay-Lussac's law, and Boyle's law) can be well understood and explained by the kinetic theory of gases, as they relate to the macroscopic properties and behaviors of gases and their constituent particles.

Carbon is deposited in the exhaust pipes of cars primarily because of incomplete combustion of petrol. When the fuel (petrol) is burned in the engine's combustion chamber, ideally, it should be fully oxidized, resulting in the production of carbon dioxide (CO2) and water vapor. However, in real-world conditions, the combustion process may not be perfect, and some of the carbon in the petrol may not fully burn. As a result, carbon particles are formed and get carried through the exhaust system.

Cations are discharged at the cathode during electrolysis.

Electrolysis is the process of using an electric current to cause a chemical reaction to take place. The cathode is the negative electrode in an electrolytic cell. It is where cations (positively charged ions) are discharged

Copper (II) ions have vacant d-orbitals. This means that they can accept a pair of electrons from a donor atom. When a copper (II) ion accepts a pair of electrons, it forms a co-ordinate covalent bond with the donor atom.

The correct order of boiling points of the compounds $NH_3$, HF, $SiH_4$, and $CH_4$ is HF, $NH_3$, $SiH_4$, $CH_4$.
The correct order of boiling points of the compounds $NH_3$, HF, $SiH_4$, and $CH_4$ is HF, $NH_3$, $SiH_4$, $CH_4$.

The boiling point of a compound is the temperature at which the vapor pressure of the liquid is equal to the atmospheric pressure. The stronger the intermolecular forces, the higher the boiling point.