Chemistry Questions and Answers

The periodic property that is used to determine whether a covalent molecule is polar or not is electronegativity.

Electronegativity is a measure of the ability of an atom to attract electrons in a chemical bond. The greater the electronegativity of an atom, the more strongly it will attract electrons.

The density of a gas is directly proportional to its molar mass. This means that gases with a lower molar mass will be less dense than gases with a higher molar mass. Nitrogen (N2) has a molar mass of 28 g/mol, which is less than that of air (approximately 29 g/mol), making it less dense than air.

Natural gas is a fossil fuel primarily composed of hydrocarbon gases. The primary component of natural gas is methane, which typically makes up a significant portion of the gas mixture. Methane is a simple hydrocarbon with one carbon atom and four hydrogen atoms (CH4). It is the main component of natural gas, often accounting for over 90% of its composition.

Melting point increases. This is because the atoms become larger as you go down the group, which means that the metallic bonds between them become stronger.

Flooding is a major consequence of global warming because as the Earth's ice caps and glaciers melt, sea levels rise. This can cause flooding in coastal areas and low-lying islands. For example, in 2019, the Netherlands experienced its worst flooding in decades, with over 10,000 homes damaged and thousands of people evacuated.

There are 5 unpaired electrons present in \(_{26}Fe^{3+}\).

The atomic number of iron is 26, so it has 26 electrons. When iron loses 3 electrons to form \(Fe^{3+}\), it loses 2 from the s orbital and 1 from the d orbital. This leaves 5 unpaired electrons in the d orbital.

The electron configuration of \(Fe^{3+}\) is [Ar]3d5. The 5 d electrons are all unpaired because Hund's rule states that electrons will occupy degenerate orbitals singly before they pair up. This is because unpaired electrons have a lower energy than paired electrons.

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.