Rates of reaction

Question 1

Describe a practical you’d use to investigate the effect of temperature on the rate of reaction:

Answer 1

1. measure out 50cm3 of sodium thiosulfate taken from a 60ºC water bath into a conical flask
2. place the flask on a cross symbol
3. measure out 20cm3 of hydrochloric acid
4. using a thermometer wait until the water has cooled down to 50ºC
5. add in the hydrochloric acid and immediately start the stop watch and start stirring
6. time how long it takes for the cross to disappear
7. repeat 1-6, changing the temperature of the sodium thiosulfate by letting it cool down to certain intervals using the thermometer.
8. plot a line graph with time taken on the y axis and temperature on the x axis

Question 2

Describe a practical you’d use to investigate the effect of concentration on the rate of reaction:

Answer 2

1. measure out 40cm3 of sodium thiosulfate and 10cm3 of deionised water into a conical flask
2. place the flask on a cross symbol
3. measure out 20cm3 of hydrochloric acid
4. add in the hydrochloric acid and immediately start the stop watch and start stirring
5. time how long it takes for the cross to disappear
6. repeat 1-6, changing the concentration of the sodium thiosulfate adjusting the sodium thiosulfate to water ratio.
7. plot a line graph with time taken on the y axis and concentration on the x axis

Question 3

Describe a practical you’d use to investigate the effect of a catalyst on the rate of reaction:

Answer 3

1. measure out 50cm3 of hydrogen peroxide into a tube.
2. fill a water bath and measuring cylinder with water, placing the cylinder upside down
3. feed a delivery tube connected to a bung inside the cylinder opening
4. measure out a 5cm3 piece of cooked liver
5. add the catalyst in and start the stop watch
6. every 20 seconds record how much gas was produced reading the measuring cylinder for 3 minutes.
7. repeat 1-6 using different catalysts
8. draw line graphs of each catalyst, with time on the x axis and volume of gas on the y axis

Question 4

Describe a practical you’d use to investigate the effect of surface area on the rate of reaction:

Answer 4

1. measure out 50cm3 of hydrochloric acid into a tube.
2. fill a water bath and measuring cylinder with water, placing the cylinder upside down
3. feed a delivery tube connected to a bung inside the cylinder opening
4. using a balance weigh out 5g of fine marble shavings
5. add the marble in and start the stop watch
6. every 20 seconds record how much gas was produced reading the measuring cylinder for 3 minutes.
7. repeat 1-6 using different sizes of marble
8. draw line graphs of each size of marble shavings, with time on the x axis and volume of gas on the y axis