JAMB Past Questions and Answers

The decomposition of hydrogen peroxide (H\(_2\)O\(_2\)) into water (H\(_2\)O) and oxygen (O\(_2\)) is an endothermic reaction because it requires energy to break the bonds in the hydrogen peroxide molecule. The process absorbs heat from the surroundings to drive the reaction.

Niels Bohr proposed the planetary model of the atom in 1913. According to this model, electrons move in circular orbits around the positively charged nucleus, much like planets orbiting the sun. However, this model has been refined in modern quantum theory.

The industrial production of ammonia is known as the Haber process. It involves the reaction of nitrogen gas (N\(_2\)) and hydrogen gas (H\(_2\)) at high temperature and pressure in the presence of a catalyst to produce ammonia (NH\(_3\)).

Eutrophication is the excessive growth of algae and aquatic plants in water bodies due to the increased availability of nutrients like nitrogen and phosphorus. This nutrient enrichment often comes from agricultural runoff, sewage, and industrial discharges.

In the kinetic theory of gases, the pressure exerted by a gas is a result of the frequent and random collisions of gas particles with the walls of the container. The force of these collisions creates pressure on the container walls.

The sum of the oxidation numbers in a neutral compound is always zero. This is because oxidation numbers represent the charge that an atom would have if all bonding were ionic. In a neutral compound, the total positive charge (from the oxidation numbers of the atoms that have positive oxidation numbers) must equal the total negative charge (from the atoms that have negative oxidation numbers).

The phase change from a liquid to a gas involves an increase in entropy. In the gas phase, molecules have higher degrees of freedom and are more dispersed compared to the liquid phase, resulting in higher entropy change.

Radon is a radioactive noble gas and is produced as a decay product of uranium and thorium in the Earth's crust. It is colorless, odorless, and tasteless, making it potentially hazardous when it accumulates in enclosed spaces.

When the temperature is decreased in a reversible reaction, the equilibrium shifts in the direction that produces heat (exothermic direction). For an exothermic reaction, this means the equilibrium position shifts to the right, favoring the forward reaction.

Hard water is water with high concentrations of dissolved ions, in particular calcium and magnesium ions