Chemistry Revision Questions

Describe the arrangement, movement and energy of solids, liquids and gasses

Solid(s) particles are extremely close together. The particles vibrate in a fixed position, and due to the ammound of energy, solids can be desicribed as a very dense state due to the ammount of energy per cm3. In a liquid(l), the particles are fairly close together, but not as close as solids. Liquids are less dense and the particles aren't in a fixed position, so they often slide past and around eachother. In a gas(g) the particles are extremely far apart. Gas is the least dense state and the particles move quickly and often bump into eachother. 

What is the conversion for a solid to gas called?

The conversion from a solid to gas is called sublimation.

What is the conversion of gas to liquid called?

The conversion from gas to liquid is called condensing. 

What happens when purple crystals of potassium manganate are put into a beaker of water?

The potassium manganate crystals start to diffuse into the water (think ribena)

What happens when ammonia and hydrochloric acid are put in a horizontal glass tube?

After a few minutes a white ring will form in the tube where the molecules of the two liquids have met. It will be closer to the end of the tube where the hydrochloric acid is because the ammonia molecules are lighter and will diffuse faster.

Describe how filteration can separate a mixture of sand and water

If the two substances are mixed together, we can separate them if one is soluble (water) and one is insoluble (sand.) When a substance is mixed, the particles pass through the filter paper, where they will be separated. The soloution that passes through the filter paper is called the filtrate. The insoluble substance that remains as a solid, because it cannot fit through the small holes in the filter paper, is called the residue.

Describe how distillation can separate a mixture of alcohol and water

Distillation is the process of heating a liquid to its boiling point, capturing the vapour and cooling the gas back to a liquid. By heating the substance (alcohol and water) at 78 degrees, you will not make the water change state. The alcohol, however, will. By catching the vapour and cooling it, you will have separated the substances.

Describe how to carry out chromotography

Simple chromatography is carried out on paper. A spot of the mixture is placed near the bottom of a piece of chromatography paper and the paper is then placed upright in a suitable solvent, eg water. As the solvent soaks up the paper, it carries the mixtures with it. Different components of the mixture will move at different rates. This separates the mixture out.

Which group are the following elements in: Lithium, Bromine and Sulphur?

Lithium is found in group 1, Bromine in group 7 and Sulpher in group 6.

What is the symbol for Sodium, Helium and Carbon?

Sodium - Na, Helium - He and…