Changes of state and conservation of mass
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Explainer Video
Summary
Changes of state and conservation of mass
In a nutshell
When a state change takes place the arrangement of particles alter. The particle arrangement will change due to a change in the particle energy.
Changes of state
Definition
A change of state refers to when one state of matter is changed into another. For a change of state to happen energy must either be supplied or given out and this will alter the arrangement of particles resulting in a change of state.
Energy in state changes
State of matter is heated (energy gain)
| 1. | Particles gain energy. |
| 2. | More particle movement, forces between particles start to weaken. State will start to expand. |
| 3. | At a certain temperature, with enough energy, particles will break free of the forces between them. |
| 4. | State change occurs. |
State of matter is cooled (energy loss)
| 1. | Particles lose energy. |
| 2. | Less particle movement, forces between particles begin to strengthen. |
| 3. | At a certain temperature, with enough energy lost, forces between particles will form. |
| 4. | State change occurs. |
Changes of state processes
process | state change | temperature change | energy change |
| 1. Melting | Solid to liquid | Heating | Energy gain |
| 2. Freezing | Liquid to solid | Cooling | Energy loss |
| 3.Evaporation/boiling | Liquid to gas | Heating | Energy gain |
| 4. Condensation | Gas to liquid | Cooling | Energy loss |
| 5. Deposition | Gas to solid | Cooling | Energy loss |
| 6. Sublimation | Solid to gas | Heating | Energy gain |
Note: Sublimation is very rare.
Conservation of mass
A state change does not involve a change in mass, only a change in energy.
Example
Explain what is happening to the solid particles during the melting process.
- Melting will result in the heating of a solid to a liquid.
- Heating will mean that the solid particles will gain energy.
- Particles will begin to move more and the forces between them will weaken.
- At a certain melting temperature, the forces between the solid particles will break free and a liquid will form.
FAQs - Frequently Asked Questions
Why is energy involved in a change of state?
The amount of energy occupied by particles will determine their arrangement and the state of matter.
During a change in state will the mass change?
The mass will not change during a state change, only the amount of energy will change.
What are the five processes for changing a state?
The five processes for changing state are: melting, evaporation, condensation, freezing and sublimation.