principles of chemistry


states of matter

Solids: In solids there are strong forces of attraction between particles, which holds them close together in fixed positions to form a very regular fixed latice arrangment. The particles dont move from thier positions so all solids keep a definite shape and volume, and dont flow like liquids. The particles vibrate, around their positions- the hotter the solid becomes the more they vibrate (causing solids to expand slightly when heated)

Liquids: In liquids, there is a weak force of attraction between the particles. Theyre randomly arranged and are free to move past each other but they tend to stick closley together. Liquids have a definite volume but dont keep a definite shape, and will flow to fill the bottom of a container. The particles are constantly moving with random motion. The hotter the liquid gets the faster they move. This causes liquids to expand slightly when heated. 

Gases: In gases teh force of attraction, is extreamly weak- theyre free to move and are far apart. The particles in gases travel in straight lines. Gases dont keep a definite shape or volume and will always fill any container. The particles move constantly and with random motion. The hotter the gas gets the faster they move. Gases either expand when heated, or their pressure increases.


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substances changing from one state to another

1. When a solid is heated its particles gain more energy.

2.This makes the particles vibrate more which weakens the forces, that holds the solid together. This makes the solid expand.

3. At certain tempuratures, particles have enough energy to break free from their positions, this is called melting, and the solid turns into a liquid.

4. When the liquid is heated, again the particles gain even more energy

5. This energy makes the particles move faster, which weakens and breaks the bonds holding the liquid together

6. At certain tempuratures the particles have enough energy to break thier bonds. This is called evaporating, and the liquid turns into a gas.

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potassium magnate and water

1. If you take a beaker of water and place some potassium magnate at the bottom, the purple colour slowly spreads out to fill the beaker

2.  This is chemistry in action. The particles of potassium magnate, are diffusing out among the particles of water

3. It's the random motion of particles in a liquid that causes the purple colour to be evenly spread out throughout the water.

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Ammonia and hydrogeon chloride

1. Aqueos ammonia gives off ammonia gas. Hydrochloric acid, gives off hydrogeon chloride gas.

2. The NH4 gas diffuses from one end of the tube and the HCL gas diffuses from the other. When they meet they react to form ammonia chloride.

3. The ring of gas forms closer to the end containing the hydrochloric acid, because the particles of ammonia are smaller and lighter, than the particles of hydrogeon chloride,  so they diffuse through the air more quickly.

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