Explanation

• The formation of hydrogen and oxygen from water, which is an example of a decomposition reaction: 2H2O → 2H2 + O2
• In this reaction, water (H2O) decomposes into hydrogen (H2) and oxygen (O2).

Explanation

• Carbon-14 is used to investigate carbon uptake and biochemical pathways in plants.
• It is a radioactive isotope that allows researchers to trace carbon through various metabolic processes.

Explanation

• Nitrogen (N2) makes up approximately 78% of the Earth's atmosphere.
• Making it the gas present in air with the highest percentage.

Explanation

• A solution is a type of mixture that is homogeneous, meaning it has a uniform composition and properties throughout.
• It is a mixture of two or more substances, where one substance (the solute) is dissolved in another substance (the solvent).

Explanation

• Lone pairs are pairs of outer shell electrons that are not used in bonding. They are also known as non-bonding pairs or unshared pairs.
• These electrons are typically found in the outermost energy level (valence shell) of an atom and are not involved in forming chemical bonds with other atoms.

Explanation

• In Group II (the alkaline earth metals), the metallic radii increase as you go down the group due to the addition of electron shells.
• As the radii increase, the mass of the atoms also increases, but the volume increases more rapidly.
• This means that the density (mass per unit volume) increases as you go down the group.

Explanation

• Ethylene bromide (C2H4Br2) is a compound that was formerly used as a scavenger in leaded gasoline to prevent the formation of lead oxide and lead sulfate deposits in engines. It reacted with the lead compounds to form a volatile lead bromide, which was then exhausted out of the engine.
• The use of leaded gasoline and ethylene bromide as a scavenger has largely been phased out due to environmental and health concerns.

Explanation

Explanation

The step "Deionize the metal" is not used in calculating lattice energy in the Born-Haber cycle.

The correct steps include:

• Ionizing the metal
• Ionizing the non-metal
• Atomizing the metal
• Calculating the energy required to form the ionic bond

Deionization is not involved as lattice energy focuses on ion formation and attraction.

Explanation

When a copper strip is placed in a solution of FeSO₄, no significant reaction occurs because copper does not have a stronger tendency to oxidize compared to iron.

The statement "Cu will be precipitated down" is because there is no source of Cu²⁺ ions in the solution to precipitate out.

Copper remains as a metal, and iron remains in the Fe²⁺ ionic form in the solution.