Chemistry Questions and Answers

1 Faraday of electricity is equal to the charge of 1 mole of electrons, which is 96,485 coulombs. The reduction of copper(II) ions in solution to copper metal requires 2 electrons per ion, so 1 Faraday of electricity will deposit 0.5 moles of copper.
1 Faraday * (2 electrons/Cu ion) / (1 mole electrons/96,485 coulombs) * (1 mole Cu/2 electrons) = 0.5 moles Cu

Amount (in moles) = Molarity × Volume
Amount (in moles) = 0.20 mol/dm³ × 100.0 cm³ / 1000 cm³/dm³ = 0.020 moles
Now, we can calculate the mass using the formula:
Mass = Amount × Molar Mass
Mass = 0.020 moles × 40.0 g/mol = 0.80 g
So, the correct answer is:0.80 g

Thermal cracking is a process used in the petroleum industry to break down long-chain alkanes (hydrocarbons) into smaller, more useful hydrocarbons. It involves the decomposition of high-molecular-weight hydrocarbons, such as heavy crude oil fractions or long-chain alkanes, into lower-molecular-weight hydrocarbons, like smaller alkanes and alkenes. During thermal cracking, high temperatures and sometimes pressure are applied to the feedstock (such as crude oil or natural gas) to initiate the decomposition reactions.

Vapour density = Relative molar mass / 2
Vapour density = 30 / 2 = 15
Therefore, the vapour density of the gaseous hydrocarbon is 15.

Phenolphthalein is an indicator that is commonly used in acid-base titrations. It is colorless in acidic solutions (pH below 8.2) and turns pink or magenta in alkaline solutions (pH above 10). In the titration of ethanoic acid (acetic acid) with sodium hydroxide (a strong base), the pH will change from acidic to alkaline as the acid is neutralized by the base

The chemical formula for sodium tetraoxosulphate (VI) is \(Na_2SO_4\). It is also known as sodium sulfate. This compound does not have any water molecules as part of its crystal structure, making it anhydrous. So, it is an example of a crystalline substance that does not possess water of crystallization.

The rate of diffusion of a gas is inversely proportional to the square root of its molar mass (Graham's law). This means that gases with a higher molar mass will diffuse more slowly than gases with a lower molar mass. Given the molar masses of the gases in the options, Oxygen (O=16.0) has the highest molar mass and therefore the lowest rate of diffusion

The term "isoelectronic" comes from the Greek words "iso" meaning "equal" and "electron" meaning "electron". Isoelectronic species are atoms, molecules, or ions that have the same number of electrons. have the same number of electrons because they have the same electron configuration. The electron configuration of an atom is the arrangement of electrons in the atom's orbitals. The electron configuration of an atom determines the chemical properties of the atom.

\(H_2SO_4\) and \(CaCl_2\) are not suitable for drying ammonia gas because they react with the gas.

Ammonia is a basic gas, and both \(H_2SO_4\) and \(CaCl_2\) are acidic. When these two substances react, they form salts that contain ammonia. This can contaminate the ammonia gas and make it unusable.

In addition, \(H_2SO_4\) is a corrosive substance, and \(CaCl_2\) can be harmful to breathe in. Therefore, it is not safe to use these substances to dry ammonia gas.

The reduction half equation for the given reaction is:

\(Cu^{2+}_{(aq)} + 2e^- → Cu_{(s)}\)

In the overall reaction, copper(II) ions (\(Cu^{2+})\) gain two electrons (2e^-) and get reduced to form solid copper (Cu) metal. This is the reduction half-reaction in the redox reaction between zinc (Zn) and copper(II) sulfate (\(CuSO_4)\).