This section of BigBang NetConnections is a growing section on the Basics of Chemistry. Soon we will be making more sections of content to The Basics of....

What are the states of matter?

SOLID. A solid can not be compressed, it has a fixed shape and the particles vibrate.

LIQUID. A liquid is random, can not be compressed, change shape to fit bottom of container and they can slide over each other.

GAS. A gas can be easily compressed. A gas spreads out to take shape of the whole containter, they move all the time, and diffuse. Higher temperature makes diffusion quicker, as does weight, a lower weight makes for quicker diffusion.

How do you change states?

A solid melts in to a liquid, while a liquid solidifies or freezes in to a solid. A liquid evaporates in to a gas, while a gas condenses in to a liquid. When you turn a solid in to a gas it is called sublimation.

When you melt and boil, a solid heats up, then keeps the same temperature while the bonds are breaking, and then it heats up, then the bonds break. This happens twice and by the end of it, it has turned to a gas. All of this activity requires energy (usually by heating).

How do I seperate substances?

Distillation requires is based on the fact that two liquids have different boiling points, and as you distill, it goes in to a jug at the end. So in one part you have a conical flask, connected to a delivery tube, and then that is set up to a test tube / boiling tube or whatever to collect what is boiled. It is condensed on the way down from a boiled gas in to a liquid.

Evaporation uses a tripod, pipe clay triangle and dish. You heat up the dish through the pipe clay T, and that makes the liquid evaporate. Left in your dish is the soluble solid.

Chromatography seperates dyes. The higher the dot on the sheet of filter paper, the more soluble the dye is. You place a dot on the filter paper with your substance, and then let water travel up by dipping one end in the water.

Filtration seperates insoluble solids and soluble liquids. You set up a conical flash with a filter and filter paper in the top. Then you put your mixture in. This is done with coffee in making filter coffee.

Reactions? Tell me about reactions.

Equations - state symbols. Same number of atoms must exist on either side.
Compounds are elements joined chemically. Same ratio of elements.
Elements - types of atoms on the periodic table.
Mixtures are elements that haven't joined, they can be sperated easily and are mixed in any proportion.

Making compounds

A compound is where two or more different elements have been chemically bonded together. The atoms cannot easily be seperated.

Diffusion

Diffusion is the random movement of particles that causes them to spread out. The speed at which diffusion occurs depends upon a number of things.

1. The temperature - the higher the temperature, the faster the rate of diffusion. The reason is because they are getting more energy to move.

2. The state - gases diffuse faster than liquids, which diffuse faster than solids. This is because solids and liquids are not compressable, while gases are. This is because liquids and solids are bonded while gas particles are far apart and not bonded.

3. The mass of the particles involved. The heavier the particle the slower the rate of diffusion.

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