Nature of Matter — NEET Chemistry MCQs with Solutions

Solution: Liquids have a definite volume but no definite shape — they take the shape of the container in which they are placed. Solids have both a definite volume and a definite shape, while gases have neither a definite volume nor a definite shape.

Solution: In solids the particles are held very close together in an orderly fashion and have almost no freedom of movement, which is why solids possess a definite shape and volume. In liquids the particles are close but can move around; in gases they are far apart and move easily and fast.

Solution: In sugar dissolved in water the sugar particles are uniformly distributed and the composition is the same throughout, so it is a homogeneous mixture. Sand–water, salt–sugar and grains–stones are heterogeneous, since their composition is not uniform and the components can be distinguished.

Solution: A mixture is simply two or more pure substances physically put together, so its components can be separated by physical methods such as hand-picking, filtration, crystallisation and distillation. Chemical methods are needed only to break down a compound, not a mixture.

Solution: Water (H₂O) is a compound: two different elements (hydrogen and oxygen) combined in a fixed ratio, separable only by chemical means. Oxygen is an element, while air and a sugar solution are mixtures of variable composition.

Solution: The states of matter are interconvertible by changing temperature and pressure. For example, on heating a solid usually melts to a liquid and then vaporises to a gas; on cooling, the gas condenses to a liquid and the liquid freezes back to a solid.

Solution: K = °C + 273.15 = 100 + 273.15 = 373.15 K. Subtracting instead of adding gives the wrong 173.15 K; 273.15 K corresponds to 0 °C (the freezing point); 212 is the Fahrenheit boiling point, not a kelvin value.