Question

1. how do we change the state of a substance? 15. what is temperature? what does it measure? 16. describe the kelvin scale.

Explanation:

1. The state of a substance can be changed by adding or removing heat energy (endothermic or exothermic processes). For example, melting occurs when heat is added to a solid to turn it into a liquid, and freezing is the reverse process when heat is removed from a liquid to turn it into a solid. Vaporization happens when heat is added to a liquid to turn it into a gas, and condensation is when heat is removed from a gas to turn it into a liquid. Sublimation is when a solid directly turns into a gas upon heating, and deposition is the reverse.
2. Temperature is a measure of the average kinetic energy of the particles in a substance. It indicates how hot or cold an object is relative to a standard. A higher - temperature object has particles with greater average kinetic energy.
3. The Kelvin scale is an absolute temperature scale. Its zero point, 0 K, is absolute zero, which is the theoretical temperature at which all molecular motion ceases. The size of a Kelvin degree is the same as a Celsius degree. The triple - point of water (the temperature and pressure at which water exists in all three states simultaneously) is defined as 273.16 K.

Answer:

1. By adding or removing heat energy through processes like melting, freezing, vaporization, condensation, sublimation, and deposition.
2. Temperature is a measure of the average kinetic energy of particles in a substance; it indicates the hotness or coldness of an object.
3. The Kelvin scale is an absolute temperature scale with 0 K as absolute zero, where molecular motion theoretically stops, and the triple - point of water is defined as 273.16 K.