States of Matter
Kuvakäsikirjoitus Teksti
- Changes of state from solid to liquid to gas: Solid to liquid is melting, liquid to solid is freezing, solid to gas is sublimation, liquid to gas evaporation and gas to liquid is condensation.
- For the test we need to know about shape, volume, arrangement of particles, energy, forces of attraction between particles and change of state processes from solid to liquid to gas.
- The basic idea in molecular shapes is called valence shell electron pair repulsion (VSEPR). It says that electron pairs, being composed of negatively charged particles, repel each other to get as far away from each other as possible. This shape is called bent or angular.
- So, what is shape?
- What is volume?
- The volume of a regular shaped solids can be calculated from their dimensions. For example, the volume of a rectangular solid is the product of its length, width, and height (l x w x h).
- What is the arrangement of particles?
- Solids are tightly packed, usually in a regular pattern. They vibrate but generally do not move.Liquids are close together with no regular arrangements. They vibrate, move about and slide past each other.Gas are well separated with no regular arrangement. They vibrate and move freely at high speeds.
- Energy is always involved in changes of state. Matter either loses or absorbs energy when it changes from one state to another. For example, when matter changes from a liquid to a solid, it loses energy. For a solid to change to a liquid, matter must absorb energy from its surroundings.
- What is Energy?
- What is Forces of Attraction?
- When two atoms are brought together and as the distance between them becomes comparable with their dimension, the positive and negative charges of each atom start influencing charges in the other atom. This gives rise to an interatomic force and changes the total energy of the pair.
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