 Chemistry: High School: 9th and 10th Grade Quiz - Rates of Reaction 3 (Questions)

This Chemistry quiz is called 'Rates of Reaction 3' and it has been written by teachers to help you if you are studying the subject at high school. Playing educational quizzes is a user-friendly way to learn if you are in the 9th or 10th grade - aged 14 to 16.

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Many factors affect rates of chemical reactions - pressure of gasses, temperature, surface area of solids, concentration and if there is a catalyst. Anything that will change the probability of particles colliding or change the energy of the collisions will affect the rate of a reaction. This is the last of three high school Chemistry quizzes looking at these factors.

When investigating rates of reaction, it is necessary to make a series of measurements over a period of time, for example, how much hydrogen is produced during the reaction of an acid with zinc. The experiment should be repeated several times and, after discarding any anomalous results, the readings averaged and plotted on a scatter graph with time along the horizontal axis. The line of best fit will usually be a curve, with the steepest gradient at the start indicating the fastest rate of reaction. Where the curve is horizontal, is shows that the reaction had finished. The conditions of the experiment can then be changed and the whole process repeated. Plotting the results on the same graph, using different colors, gives a quick and easy visual interpretation, from which you can write your conclusion.

When working out rates of reaction mathematically, as higher tier candidates are more likely to do, dividing the amount of reactant used (or product formed) by the time taken gives a valid rate. This is effectively the same as working out the gradient of a graph. If 15 cm3 of carbon dioxide were released in the first 20 seconds of a reaction, the rate would be 0.75 cm3/s. Later in the reaction, it may take 45 seconds to produce 10 cm3 of carbon dioxide, in which case the rate would have dropped to 0.22 cm3/s. This slowing down of the rate occurs because the concentration of one or both of the reactants changes during the reaction. Professional scientists usually refer to the initial rate of reaction, in other words the rate at the very start.

How would a decrease in temperature affect the rate of a reaction? What about surface area? Have a go at this quiz and test your knowledge of the factors which affect rates of reaction, such as temperature, surface area or pressure.

1. Which of the following is NOT a disadvantage of using a catalyst in a chemical reaction?
 [ ] They can be reused multiple times [ ] If a reaction is going too fast, simple mistakes can be made [ ] They can be poisoned by impurities and stop working [ ] They can be expensive
2. On an energy level diagram, what effect would adding a catalyst have to the reaction on the line showing the energy for a reaction?
 [ ] It would go higher [ ] It would not go as high [ ] It would be the same [ ] It would be a straight line not a curve
3. What units do we use to measure concentration?
 [ ] kmol/dm3 [ ] mol/dm3 [ ] mol/dm2 [ ] mol/dm
4. What apparatus is used to measure the volume of gas given off in a reaction?
 [ ] Stop clock [ ] Ruler [ ] Gas syringe [ ] Test tube
5. Which of the following statements about collisions is correct?
 [ ] Only fast-moving particles collide with each other [ ] All colliding particles have the same amount of energy [ ] Reactions can only happen if the colliding particles have enough energy [ ] All colliding particles are at the same temperature
6. Calcium carbonate (marble) reacts with hydrochloric acid to produce water, carbon dioxide and calcium chloride. Which of the following combinations is likely to result in the fastest rate of reaction?
 [ ] 1g of marble chips with 50ml of hydrochloric acid at 20 °C [ ] 1g of marble powder with 50ml of hydrochloric acid at 20 °C [ ] 1g of marble chips with 50ml of hydrochloric acid at 30 °C [ ] 1g of marble powder with 50ml of hydrochloric acid at 30 °C
7. Platinum is used as a catalyst in the production of nitric acid. Which of the following statements is correct?
 [ ] The catalyzed reaction requires more energy than the uncatalysed reaction [ ] The catalyzed reaction will produce more nitric acid than the reaction without platinum [ ] The mass of platinum will remain the same throughout the reaction [ ] The particles in the catalyzed reaction will have more energy than the particles in a reaction without the platinum
8. Which of the following does NOT affect the rate of a chemical reaction between a solid and a liquid?
 [ ] Concentration [ ] Temperature [ ] Altitude [ ] Surface area
9. Which of the following statements about the effect the size of the pieces of a solid on the rate of a chemical reaction is true?
 [ ] The smaller the pieces, the bigger the surface area so there is more surface area to be attacked [ ] The bigger the pieces, the smaller the surface area, so there is more surface area to be attacked [ ] The bigger the pieces the bigger the surface area so there is more surface area to be attacked [ ] The smaller the pieces, the smaller the surface area so there is more surface area to be attacked
10. What is activation energy?
 [ ] The maximum energy that particles need to change into a new substance [ ] The minimum energy required to break the bonds of the colliding chemicals [ ] The minimum energy that particles need to change into a new particle [ ] The maximum energy that particles need to change into a new substance when they collide with other particles Chemistry: High School: 9th and 10th Grade Quiz - Rates of Reaction 3 (Answers)
1. Which of the following is NOT a disadvantage of using a catalyst in a chemical reaction?
 [x] They can be reused multiple times [ ] If a reaction is going too fast, simple mistakes can be made [ ] They can be poisoned by impurities and stop working [ ] They can be expensive
Catalysts are not used up in chemical reactions
2. On an energy level diagram, what effect would adding a catalyst have to the reaction on the line showing the energy for a reaction?
 [ ] It would go higher [x] It would not go as high [ ] It would be the same [ ] It would be a straight line not a curve
A catalyst lowers the activation energy or energy required for the reaction to take place. Make sure that you can label energy level diagrams before any chemistry exam
3. What units do we use to measure concentration?
 [ ] kmol/dm3 [x] mol/dm3 [ ] mol/dm2 [ ] mol/dm
Moles per cubic decimetre
4. What apparatus is used to measure the volume of gas given off in a reaction?
 [ ] Stop clock [ ] Ruler [x] Gas syringe [ ] Test tube
You can also use apparatus such as a measuring cylinder, a graduated test tube or even a burette
5. Which of the following statements about collisions is correct?
 [ ] Only fast-moving particles collide with each other [ ] All colliding particles have the same amount of energy [x] Reactions can only happen if the colliding particles have enough energy [ ] All colliding particles are at the same temperature
If there is sufficient energy involved in a collision between particles, the bonds will break
6. Calcium carbonate (marble) reacts with hydrochloric acid to produce water, carbon dioxide and calcium chloride. Which of the following combinations is likely to result in the fastest rate of reaction?
 [ ] 1g of marble chips with 50ml of hydrochloric acid at 20 °C [ ] 1g of marble powder with 50ml of hydrochloric acid at 20 °C [ ] 1g of marble chips with 50ml of hydrochloric acid at 30 °C [x] 1g of marble powder with 50ml of hydrochloric acid at 30 °C
Increasing the surface area and the temperature will increase the rate of reaction greatly
7. Platinum is used as a catalyst in the production of nitric acid. Which of the following statements is correct?
 [ ] The catalyzed reaction requires more energy than the uncatalysed reaction [ ] The catalyzed reaction will produce more nitric acid than the reaction without platinum [x] The mass of platinum will remain the same throughout the reaction [ ] The particles in the catalyzed reaction will have more energy than the particles in a reaction without the platinum
As the platinum does not take part in the reaction itself, it does not gain or lose mass
8. Which of the following does NOT affect the rate of a chemical reaction between a solid and a liquid?
 [ ] Concentration [ ] Temperature [x] Altitude [ ] Surface area
Carrying out the reaction at a different altitude would affect the pressure. Changes in pressure affect only reactions involving gasses
9. Which of the following statements about the effect the size of the pieces of a solid on the rate of a chemical reaction is true?
 [x] The smaller the pieces, the bigger the surface area so there is more surface area to be attacked [ ] The bigger the pieces, the smaller the surface area, so there is more surface area to be attacked [ ] The bigger the pieces the bigger the surface area so there is more surface area to be attacked [ ] The smaller the pieces, the smaller the surface area so there is more surface area to be attacked
The larger surface area means that there are more particles available to be involved in collisions. It is only ever the surface layer of particles of solids that are involved in reactions
10. What is activation energy?
 [ ] The maximum energy that particles need to change into a new substance [x] The minimum energy required to break the bonds of the colliding chemicals [ ] The minimum energy that particles need to change into a new particle [ ] The maximum energy that particles need to change into a new substance when they collide with other particles
Reactions involve bonds being broken followed by new, different bonds being formed