Which condition affects the state of matter observed for a particular substance?

The observed state of matter for a particular substance—solid, liquid, or gas—is primarily influenced by temperature and pressure. Temperature affects the energy of the particles within a substance; as temperature increases, the particles gain energy and move more vigorously, which can lead to a transition from solid to liquid (melting) or from liquid to gas (evaporation). Conversely, lowering the temperature can cause gas to condense into a liquid or a liquid to freeze into a solid.

Pressure also plays a crucial role, especially in gases. Increasing pressure on a gas can force particles closer together, potentially causing a change to a liquid state if the pressure is sufficiently high and the temperature is low enough. Therefore, by manipulating temperature and pressure, one can control the state of matter of a substance, making these two factors key determinants in the physical properties and behavior of materials.

The other options, while related to different physical properties, do not fundamentally influence the state of matter in the same way. Size and shape pertain to the physical dimensions of an object rather than its state. Weight and length are measurements that do not affect how matter exists in different states. Time and distance are unrelated to the states of matter, as they pertain more to physical motion and duration