what is the temperature at which a substance changes from a solid to a liquid called
True. Water can change from a solid state (ice) to a liquid state (water), and from a liquid state to a gaseous state (steam) depending on the temperature and pressure conditions.
The change that occurred to the water is a physical change. In this case, the water changed from a liquid state to a solid state without altering its chemical composition.
Water evaporating is only a physical, not a chemical change because the water can be brought back easily to its original state where as burning a match is a chemical change.
This is an experiment. it will change from liquid to solid.
An example of a change of state as a physical change is the melting of ice into water. This change involves a solid (ice) converting into a liquid (water) due to an increase in temperature, but the substance itself remains the same chemically.
The thermal energy required to change state is taken from the environment; which in this case is the melt water.
Better to state it a biochemical change if required can state it chemical change
It is a process that can change the state of something, which can if required be undone. Example, you can freeze water into ice, then reverse the process by allowing the ice to melt into water.
No. The quantity of energy required to raise the temperature of water is different depending on the phase of water. This is especially true at or near a phase transition as thermal energy is absorbed during a phase transistion thus altering the amount of energy required to raise the temperature of said water.
The evaporation of water is an example of a physical change, where water changes from its liquid state to a gaseous state without any change in its chemical composition.
Yes there must be achange;but heat is required to change liquid state into gaseous state.
This is called a change in the physical state of the substance. For example formation of ice from water is a change in the physical state of water.
Heat
True. Water can change from a solid state (ice) to a liquid state (water), and from a liquid state to a gaseous state (steam) depending on the temperature and pressure conditions.
It is the amount of energy required to change the state of 1kg of a substance with no change in temperature.
No, the process of water being split into hydrogen and oxygen is a chemical change, not a change of state. During this process, new substances are formed through a chemical reaction, rather than a change in the physical state of the water molecules.
Assuming that it is not highly contaminated, water in it's liquid state will always be denser than water in a solid state. Being less dense, ice will float in water. As for boiling water, I'm not aware of any change in density of boiling water until it reaches it's required energy level to make the phase change to steam which is a gas and is no longer considered boiling water.