Researching Chemistry

Question 1

Filtration

Answer 1

Filtration is used to seperate a liquid from a solid

Question 2

Distillation

Answer 2

Distillation is used to seperate a mixture of liquids with different boiling points. The mixture is heated until the compound with the lowest bp boils. The vapour passes out of the distilling flask into the condenser. The vapour condenses and collects in the receiving flask.

Question 3

Volumetric Analysis

Answer 3

In volumetric analysis:
* the volume markings on beakers provide only a rough indication of volume.
* measuring cylinders generally provide sufficient accuracy for prepartive work, but for analytical work, burettes, pipettes and volumetric flasks are more appropriate.

Question 4

Methods of Heating

Answer 4

Bunsen burner - achieve high temps but never used for highly flammable compounds. Temp is hard to control accurately and they don’t apply heat evenly

Heating mantle/hot plate - can be used to heat flammable compounds, temp can be controlled reasonably well. Takes some time to reach desired temp.

Water bath - can be used to heart flammable compounds, temp controlled accurately. Can’t go over 95 degrees

Question 5

Indicators

Answer 5

Indicators are used to determine the end-point of a reaction through colour change.

Question 6

Preparing A Standard Solution

Answer 6

1. Weight the sample
2. Dissolve in a small volume of deionised water in a beaker
3. Transfer the sample to a standard (volumetric) flask
4. The beaker is rinsed and the risnings are also poured into the standrard flask.
5. The flask is made up the mark adding the last few drops of water using a dropping pipette.
6. The flask is stoppered and inverted several times to ensure thorough mixing of the solution.

Question 7

Methods of Improving an Experiment

Answer 7

• Method of heating
• Ways of removing inaccuracies
• Method os stopping heat being lost to surroundings - heat shield
• Equipment used
• Repeating to ensure reliable results