chemistry - particles and mixtures

What is diffusion?

Diffusion is the spreading out of particles from an area of high concentration to an area of low concentration.

Solution definition -

A mixture of a solute and a solvent that does not separate out

Solute definition -

The substance that is being dissolved

Solvent definition -

The liquid the solute is dissolving into

Saturated solution definition -

A solution where no more solute can be dissolved in the solvent as the maximum amount of solute has been dissolved.

What is the measurement for solubility?

Grams of solute / 100 grams of solvent

How do you increase solubility in a solid?

By increasing the temperature

What is the equation for solubility?

Why does it take time for gas particles to diffuse through air?

Particles move in random directions, they also collide with particles on the air which slows them down.

What is an element?

only contains one type of atom

What is an atom?

The smallest part of an element that can still be recognised as an atom

what is a molecule?

Two or more atoms that are chemically bonded,

What is a mixture?

Two or more substances that are not chemically bonded

What is an isotope?

Isotopes are different atomic forms of the same element, which have the same number of protons but a different number of neutrons.

What is Ar in an equation?

Relative atomic mass

How do you find Ar?

Is a mixture a pure substance?

No so it will ment or boil gradually over a range of temperatures.

What is filtration used for?

Separating an insoluble solid from a liquid

Describe the process of filtration:

Place filter paper into a funnel and pour your mixture into it. The liquid part of the mixture runs through the filter paper, leaving behind a solid residue.

What is crystallisation used for?

Separating a soluble solid from a solution

Describe the process of crystallisation:

• Pour the solution into an evaporating dish and heat it up. As the water evaporates, he solution will become more concentrated.

• Once some of the water has evaporated or crystals start to form remove the dish from the heat and let the solution cool down.

• The salt should start to form crystals as it becomes insoluble in the cold and there is a highly concentrated solution.

• Filter the crystals out of the solution and leave them in a warm place to dry.

How would you seperate salt and water?

Filtration and crystallisation.

Describe how you would seperate rocks and sand:

1) grind up the rock salt using a pestle and mortar

2) dissolve it in a beaker and stir

3) filter through filter paper in a funnel

4) evaporate in an evaporating dish. (Crystallisation)

How does chromatography work?

• different dyes will move up the paper at different rates

• Some will stick to the paper and other will dissolve in the solvent and move up the paper

• The distance the dyes travel up the paper depends on the solvent and the paper you use.

What should you use to draw the base line in chromatography?

Pencil

What equation do you use to find the Rf value in chromatography?