Palm oil from a bottle flows out more easily after it has been heated because the

Analyze the question: Why does heated palm oil pour more easily? This is about how a liquid flows, which is a property called viscosity.

Concept: Viscosity is a liquid's resistance to flow. It comes from the intermolecular (cohesive) forces between the liquid's molecules.

• When a liquid is heated, its molecules gain kinetic energy and move faster.
• The attractive forces between the molecules become less effective.
• So the viscosity decreases and the liquid flows more easily.

(Palm oil is often semi-solid or very thick at room temperature, so this effect is very noticeable.)

Checking each option:

• A. Wrong. Heating does increase the speed of the molecules.
• B. Correct. Heating reduces the viscosity of the oil, so it flows more easily.
• C. Wrong. Molecules do not "force each other out." This is not a scientific explanation.
• D. Wrong. Heating does not increase adhesion to the bottle. If adhesion increased, the oil would cling to the glass and flow less easily.

Exam tip: Remember that for liquids, higher temperature means lower viscosity (honey, palm oil and engine oil all flow better when warm). For gases it is the opposite: viscosity increases with temperature. JAMB likes to test this contrast.