seperating mixtures

Question 1

Give examples of pure and impure substances

Answer 1

pure: water, carrots
impure: sausages, chips

Question 2

Identify some common mixtures

Answer 2

Salt water, coffee etc.

Question 3

Identify the solute and solvent in common mixtures

Answer 3

Solution 1: solute: salt, solvent: water
Solution 2: solute: ground coffee, solvent: water
Solution 3: solute: copper sulphate, solvent: water

Question 4

What is the most common solvent

Answer 4

water

Question 5

Distinguish between solutions and suspensions

Answer 5

The difference between a suspension and a solution is that a suspension is a mixture that includes a gas or liquid mixed with an INSOLUBLE substance. Whilst a solution is a mixture that includes a gas or liquid mixed with a SOLUBLE substance.

Question 6

Define colloid

Answer 6

A mixture in which extremely small particles of one substance are spread evenly throughout another substance.

Question 7

Define Emulsion

Answer 7

Emulsion is a colloid with droplets of one liquid spread evenly through another.

Question 8

Describe and compare the processes of filtering, sieving, decanting and centrifuging

Answer 8

Filtering, decanting, sieving and centrifuging are all different ways of separating insoluble substances from mixtures. Filtering is the process of pouring the mixture through a filter paper to catch the undissolved solids in the paper whilst the liquid or filtrate is caught in container below. Sieving is the process of using a fly screen like material to separate solid particles from mixtures. Sieves also come in different sizes of holes for different mixtures. In the decantation process the solid is allowed to fall and settle at the bottom, and then the liquid is poured off. Centrifuging is the process when the mixture is placed in a container and spun at very high speeds to separate the solid from the liquid. All of these processes are different ways to separate mixtures and all do a similar job. But one process may be better for a certain mixture than a another.

Question 9

Compare the effectiveness and limitations of these processes.

Answer 9

The effectiveness of these processes is that they all are simple ways of seperate get mixtures however some take longer and some use expensive items.

Question 10

What is s the difference between oure and impure substances?

Answer 10

The difference between pure and impure substances is that pure substances only contain one kind of particle, whilst impure substances can contain more than one particle mixed together.

Question 11

Describe the processes of distillation, evaporation, crystallisation and chromatography

Answer 11

Evaporation separates the water by evaporating it naturally from a solution whilst the solute stays behind.

Distillation is the process of separating a solute from a solvent by heating the solution to 100 degrees in the boiling flask then transports the gas (evaporated water) through a condenser which is outlined with cold water to cool the gas and finally the condenser slowly seeps pure water into the conical flask

Crystallisation is the process of using evaporation, blue copper sulphate crystals and heating them until they dissolve and are saturated and a paper clip hanging off some cotton is all for the process of making crystals.

Chromatography is the process of using a special paper called chromatography paper to be used for forensic evidence to test what substance was used.