A liquid has a density of 1.2 g/cm³. What is the mass of 250 cm³ of this liquid (Density of materials) (Density of materials; equation and unit focus: Calculate density when mass and volume are known) (Density of materials; equation and unit focus: Calculate density when mass and volume are known)

The correct answer is 300 g.

Boundary lens: Keep this separate from nearby specification points that use similar words but test a different idea. This question asks: A liquid has a density of 1.2 g/cm³. What is the mass of 250 cm³ of this liquid (Density of materials) (Density of materials; equation and unit focus: Calculate density when mass and volume are known) (Density of materials; equation and unit focus: Calculate density when mass and volume are known). The correct response is 300 g, because density links mass and volume, so the answer must preserve which quantity is being calculated. In Density of materials, the marking point should connect directly to calculate density when mass and volume are known. If the question includes values, the working must keep the appropriate unit and operation; if it is an explanation, it must name the relevant particle behaviour or energy change. This item belongs to Changes of state and the particle model, so avoid answers that switch to a different quantity, confuse heat with temperature, or describe gas pressure without collisions when collisions are the reason. Checkpoint 22 is distinct because it uses this exact question context and the boundary lens rather than a generic particle-model sentence.