Examples of Changing States Examples of matter changes are melting (changing from solid to liquid), freezing (changing to a solid from a liquid), evaporation (changing from liquid to gas) and condensation (changing from gas to a liquid).

Common changes of state include melting, freezing, sublimation, deposition, condensation, and vaporization.

Liquid to Gas A change of state is the change of a substance from one physical form to another. All changes of state are physical changes. The particles have different amounts of energy when the substance is in different states.

Common changes of state include melting, freezing, sublimation, deposition, condensation, and vaporization. These changes are shown in Figure below.

During a change of state, a substance must gain energy from the environment or lose energy to the environment but the total amount of energy is conserved. Removing enough energy from a gas causes a gas to change into a liquid or a solid. Adding enough energy to a liquid or a solid causes it to change into a gas.

The change from the liquid state to the solid state is called freezing. As the liquid cools, it loses thermal energy. As a result, its particles slow down and come closer together.

Changing state Transferring energy to or from a substance can change its state. Heating a substance in the solid state will cause it to melt , which changes it to the liquid state. Continued heating will cause the substance to evaporate or boil, which changes it to the gas state.

Melting is a process that causes a substance to change from a solid to a liquid. Melting occurs when the molecules of a solid speed up enough that the motion overcomes the attractions so that the molecules can move past each other as a liquid.

Q: Why is energy always involved in changes of state? Particles of a gas have more energy than particles of a liquid, and particles of a liquid have more energy than particles of a solid. Therefore, in order for matter to change from a solid to a liquid or from a liquid to a gas, particles of matter must absorb energy.

Physical changes that involve a change of state are all reversible. Other changes of state include vaporization (liquid to gas),freezing (liquid to solid), and condensation (gas to liquid).

When water changes state in the water cycle, the total number of water particles remains the same. The changes of state include melting, sublimation, evaporation, freezing, condensation, and deposition. All changes of state involve the transfer of energy.

In order for the molecules to actually separate from each other, more energy must be added. This energy, called heat of fusion or heat of melting, is absorbed by the particles as potential energy as the solid changes to a liquid.

Answer: Statement-1 : Change in internal energy in the melting process is due to change in internal potential energy. Statement-2 : This is because in melting, distance between molecules increases but temperature remains constant.

Heat is probably the easiest energy you can use to change your physical state. The atoms in a liquid have more energy than the atoms in a solid. There is a special temperature for every substance called the melting point. For water, the temperature needs to be a little over zero degrees Celsius (0oC) for you to melt.

Sublimation

Deposition refers to the process in which a gas changes directly to a solid without going through the liquid state. For example, when warm moist air inside a house comes into contact with a freezing cold windowpane, water vapor in the air changes to tiny ice crystals.

Hydrogen is a gas at STP and platinum is solid. Hence, Hydrogen gas adsorbed on the surface of platinum is an example of gas in solid solution.

Sublimation is the conversion of a substance from the solid to the gaseous state without its becoming liquid.

At a certain temperature, the particles in a liquid have enough energy to become a gas. The process of a liquid becoming a gas is called boiling (or vapourization), while the process of a gas becoming a liquid is called condensation.

When a gas turns into a liquid, the process is called condensation. The reverse process, when a liquid turns into a gas, is called evaporation or boiling.

Evaporation happens when a liquid turns into a gas.

The liquid can be changed in phase transformation to a gas by evaporation and a gaseous phase can be changed into liquid by condensation under conditions of high pressure and low temperature. E.g. to change an everyday gas such as nitrogen into a liquid we need to cool it down below about −200oC.

Explanation: Evaporation is the process of a liquid turning into its gaseous form. When a liquid hits its boiling point, it will evaporate and turn into gas. It can release vapor as well.

Water can occur in three states: solid (ice), liquid, or gas (vapor).

Water exists in three forms : solid, liquid and gas. (1) Water is present in solid form (as snow and ice) on snow-covered mountains, glaciers and as ice caps on the poles of the earth. (2) Water is present in liquid form in oceans, rivers, lakes, ponds and under the ground.

The States of Water: solid, liquid, gas. Water is known to exist in three different states; as a solid, liquid or gas. Clouds, snow, and rain are all made of up of some form of water.

The sources of water are – Lakes, Rains, Ponds, Wells ,Glaciers ,dams and rivers.