C6 Rates Of Reactions

Question 1

Rate of reaction equation

Answer 1

Amount of reactant used or amount of product formed / time

Question 2

RP5: effect of concentration on rates of reaction (part a (cross))

Answer 2

1) add 2cm 3 of sodium thiosulfate to a mini tube in a tub over a cross
2) add 8 cm 3 water
3) add 2cm 3 of hydrochloric acid into the tube, stir and start timer
4) stop the clock when you no longer see cross
6) repeat, but change the concentration of thiosulfate and water each time.
HYPOTHESIS: a precipitate will be formed quicker if the concentration of the reactants is greater

Question 3

Variables of RP5 part a (cross)

Answer 3

Dependant : time taken for cross to disappear
Indépendant : concentration of sodium thiosulftae
Control : amount of hydrochloric acid added

Question 4

RP5 : effects of concentration on rates of reaction part b (gas cylinder)

Answer 4

1) set up an upside down measuring cylinder filled with water in a bowl of water attached to a delivery tube and bung
2) add 50cm 3 hydrochloric acid to a flask
3) add 3cm 3 of magnesium ribbon
4) quickly attach bung to flask and start timer
5) record the volume of gas every ten seconds until gas stops being produces
6) repeat with different concentrations of hydrochloric acid

Question 5

Variables of RP5 part b (gas in cylinder)

Answer 5

Dependant : volume of gas produced
Independent: hydrochloric acid concentration
Control: magnesium a amount