2. Experimental Techniques

Question 1

Measurement

Answer 1

Time - Stopwatch or clock

Temperature - Thermometer

Mass - Balance

Volume - Beaker, Burette, Pippette, Measuring Cylinder, Gas syringe

Question 2

Paper Chromotography

Answer 2

Number of rings/ dots : number of substances
If two dots travel the same distance up the paper they are the same.

Rf value : Distance moved by solute / Solvent front

Question 3

Filtration

Answer 3

Mixture goes in funnel with filter paper into a flask
Residue stays at the top
Filtrate goes through

Question 4

Crystallisation

Answer 4

Some of the water in the solution is evaporated to make it more concentrated
A drop is paced on a slide to check if crystals are forming
Solution is left to cool and crystalise
Crystals are filtered to remove solvents

Question 5

Simple Distillation

Answer 5

Impure liquid is heated
It boils and the steam rises into the condeser
Impurities are left behind
The steams is condensed and the pure liquid drops into the beaker

Question 6

Fractional Distillation

Answer 6

Removes a liquid from a mixture of liquids

Mixture is heated to evaporate substance with the lowest b.p

Question 7

Separating a mixture of 2 solids

Answer 7

Can. E done by dissolving on in an appropriate solvent

Then filter one and extract the other from solution by evaporation