2023 - JAMB Chemistry Past Questions and Answers - page 1

If a reversible reaction is subjected to a decrease in temperature, the position of equilibrium will shift in the direction that absorbs heat. This shift is dictated by Le Chatelier's principle.

In general terms:
- If temperature decreases, the reaction will shift in the endothermic direction (the direction that absorbs heat).
- If temperature increases, the reaction will shift in the exothermic direction (the direction that releases heat).

So, for the given scenario of a decrease in temperature: The position of equilibrium shifts to the left.

This is because shifting to the left corresponds to the endothermic direction, helping to absorb the reduced external heat.

Temporary hardness in water is caused by the presence of bicarbonate ions (HCO₃⁻) which can be removed by boiling. When water is heated, bicarbonate ions decompose to form carbonate ions (CO₃²⁻), water, and carbon dioxide. The carbonate ions are insoluble and can be removed by precipitation.

So, the correct answer is Boiling

The type of salt found in antacid medications that is used to relieve heartburn and indigestion is Magnesium chloride.

Antacids often contain compounds such as magnesium hydroxide (Mg(OH)₂) or magnesium carbonate (MgCO₃), which react with stomach acid to neutralize excess acid and provide relief from heartburn and indigestion.

At room temperature (around 20-25 degrees Celsius) and standard pressure, chlorine gas is in the gaseous state

Therefore, the correct answer is Gas

Water is often referred to as the "universal solvent" because it can dissolve a wide variety of substances due to its polar nature.

Therefore, the correct answer is: Water can dissolve a wide variety of substances due to its polar nature.

The chemical structure of soap and detergent molecules typically consists of a hydrophilic (water-attracting) head and a hydrophobic (water-repelling) tail. This structure allows soap and detergent molecules to interact with both water and oils/greases.

Therefore, the correct answer is Hydrophilic head and hydrophobic tail.

An alkene contains at least one carbon-carbon double bond (C=C). A double bond consists of one sigma (\(\sigma\)) bond and one pi (\(\pi\)) bond. Since the question specifies an alkene, and it is implied that it has *one* double bond, the number of pi bonds will be 1. However, the question does not say anything about having only one double bond. The question describes an alkene, and the options refer to the total number of pi bonds. Since a double bond consists of one \(\pi\) bond, we must determine how many double bonds exist in a six-carbon chain. If we assume it has only one double bond, it has one \(\pi\) bond. If we interpret the question as asking about a general alkene with six carbon atoms and we can have multiple double bonds. The number of \(\pi\) bonds must be greater than or equal to 1. Since none of the answers say 1 or greater than 1, the question could be flawed. However, based on the options, let's consider the maximum possible number of \(\pi\) bonds: if we have 3 double bonds (each with one \(\pi\) bond and one \(\sigma\) bond), we would then have a total of 3 \(\pi\) bonds in the six-carbon structure. Therefore, the answer is 3.

When a molecule has three bonding pairs and no lone pairs around the central atom, its molecular geometry is Trigonal Planar.

The solubility product constant (Ksp) is used to determine the concentration of a solute in a saturated solution. This means it helps in expressing the equilibrium concentrations of ions in a saturated solution.

In summary, the kinetic theory of gases highlights that the pressure of a gas is primarily caused by the frequent and energetic collisions of gas particles with the walls of the container.

1. Constant Motion: Gas particles are in continuous, random motion. They move in straight lines until they collide with another particle or the walls of the container.

2. Collisions with Container Walls: The pressure exerted by a gas is a result of the countless collisions of gas particles with the walls of the container. Each collision imparts a force on the walls, and the cumulative effect of these collisions leads to the overall pressure exerted by the gas.