2 CGP Combined Science
Course Summary
PREVIEW MATERIAL
TOPIC 6
Practicals:
- Rate of Reaction
1. Measure the speed of a reaction that produces a gas by using a mass
balance
2. As the gas is released measure the mass of the flask
3. Take measurements at regular intervals and plot rate of reaction graph.
4. Alternatively use gas syringe to measure gas given off
- Measuring Two Rates
1. Add a set volume of dilute sodium thiosulfate to a conical flask
2. Place the flask on a piece of paper with a cross
3. Add dilute HCl and start a stopwatch
4. Time how long it takes for the cross to disappear
5. Repeat experiment with different concentrations of one of the reactants
6. Compare results
Rates of Reaction and Factors Affecting Them
1. On a rate of reaction graph, what does the line getting steeper show?
A Faster reaction
2. What does a flat line on a graph of the amount of products against time show?
, That the reaction has finished
PAPER 2 PRACTICALS & SUMMARY QUESTIONS AND ANSWERS
TOPIC 6
Practicals:
- Rate of Reaction
5. Measure the speed of a reaction that produces a gas by using a mass
balance
6. As the gas is released measure the mass of the flask
7. Take measurements at regular intervals and plot rate of reaction graph.
8. Alternatively use gas syringe to measure gas given off
- Measuring Two Rates
7. Add a set volume of dilute sodium thiosulfate to a conical flask
8. Place the flask on a piece of paper with a cross
9. Add dilute HCl and start a stopwatch
10. Time how long it takes for the cross to disappear
11. Repeat experiment with different concentrations of one of the reactants
12. Compare results
Rates of Reaction and Factors Affecting Them
1. On a rate of reaction graph, what does the line getting steeper show?
Faster reaction
2. What does a flat line on a graph of the amount of products against time show?
That the reaction has finished
3. What two factors relating to the collisions between particles influence the rate of a
reaction?
Collision frequency and energy transferred during the collision
4. What are the four factors that affect the rate of a chemical reaction?
Temperature, Surface area, Concentration, Presence of a Catalyst
5. Why does increasing the temperature of a reaction mixture increase the rate of a
reaction?
- When the temperature increases the particles move faster
- Faster moving particles means more frequent collisions
- Frequent collisions mean the reaction will take place more quickly
6. Other than increasing the temperature, describe two ways of increasing the rate of
reaction between a solution and a solid.
- Increasing Surface Area: more area for collisions to take place
- Increased Concentration: More particles in the same amount of water, more
frequent collisions