Chemistry Required Practicals

Question 1

Soluble salt from an insoluble oxide or carbonate

Answer 1

Independent Variable: Concentration and amount of
magnesium carbonate
Range: N/A
Dependent Variable: N/A
How it was measured: N/A
Control Variable: Volume of dilute sulphuric acid
Additional Facts: Forms crystals

Question 2

Aqueous solutions are electrolysed (using inert electrodes)

Answer 2

Independent Variable: Electrolyte/aqueous solution
Range: Copper chloride, calcium nitrate, silver
sulphate, potassium bromide, sodium iodide,
sulphuric acid
Dependent Variable: Substance formed at anode and
cathode
How it was measured: N/A
Control Variable: Electrode, voltage
Additional Facts:

Question 3

Temperature change in reacting solutions

Answer 3

Independent Variable: Temperature
Range: N/A
Dependent Variable: Temperature
How it was measured: Thermometer in degrees C
Control Variable: Volume of sodium hydroxide, volume
of hydrochloric acid added and
concentration of HCL
Additional Facts:

Question 4

Changes in concentration affect rate of reaction (measuring volume of gas produced)

Answer 4

Independent Variable: Concentration
Range: N/A
Dependent Variable: Volume of gas produced
How it was measured: Gas syringe
Control Variable: volume of HCL and mass of
magnesium
Additional Facts:

Question 5

Changes in concentration affect rate of reaction (colour change)

Answer 5

Independent Variable: Concentration
Range: N/A
Dependent Variable: Colour change
How it was measured: N/A
Control Variable: Volume of sodium thiosulfate and
volume of HCL
Additional Facts: Turbidity = cloudiness of a solution

Question 6

Paper chromatography (difference between coloured solutions)

Answer 6

Independent Variable: Different solutions
Range: Unknown, copper 2, iron 2 and iron 3
Dependent Variable: Different metal ions in unknown
How it was measured: comparing unknown to other samples.
Control Variable: Water, distance from bottom of chromatography paper, chromatography paper
Additional Facts: If the unknown has dots at the same places as other samples it contains them.

Question 7

Chemical tests (identify unknown ions)

Answer 7

Independent Variable: Test
Range: Flame, anion and cation
Dependent Variable: N/A
How it was measured: N/A
Control Variable: Substance tested.
Additional Facts: Specific metal ions are listed on Chemical analysis

Question 8

Analysis and purification of water samples

Answer 8

Independent Variable: Water sample
Range: Sea, fresh, ground, purified
Dependent Variable: N/A
How it was measured: N/A
Control Variable: Apparatus and technique used
Additional Facts: