Practical Chemistry Challenge Questions 2/4 Markers

Question 1

How can you measure how surface area and concentration affect rate of reaction

Answer 1

Attach a gas syringe to a beaker containing HCL with marble chips
Measure the volume of gas produced using the syringe and take readings at regular time intervals
For surface area, repeat with same volume and concentration of acid, but more crunched up marble
For concentration, repeat with the same mass and area of marble, but different concentrations of acid

Question 2

How can you measure the effect of a catalyst on rate of reaction using hydrogen peroxide

Answer 2

Use a measuring cylinder to add hydrogen peroxide and pour it into a conical flask
Connect a gas syringe to a delivery tube
Add the catalyst
Immediately attach the bung
Measure the amount of gas produced every 10 seconds for 1 minute

Question 3

How can you measure the effect of temperature on rate reaction

Answer 3

Add hcl and sodium thiosulphate to a beaker
Place the beaker onto a piece of paper with a black cross on it
Heat using a water bath
Add HCL to beaker
Record time taken for black cross to disappear through the cloudy yellow sulphur produced

Question 4

Combustion calorimetry

Answer 4

Use a screen to reduce droughts
50g of water in copper can and record temperature
Weigh spirit burner and lid
Stir the water to allow even heat distribution
Put out the flame and immediately measure of the final temperature of the water
And spirit burner and lid to reduce heat loss by evaporation

Question 6

How can you make a soluble salt using an insoluble base and an acid

Answer 6

Heat the acid in a water bath, in a fume cupboard to avoid fumes releasing into the room
Add the base to the acid which will react to produce a soluble salt
If the base is in excess, the solid will sink
Further off the solid and gently heat to evaporate water
Crystallisation occurs
Filter again and leave to dry