1. Describe how the concentration of reactants affects the speed of
reaction?
As the reactant concentration increases the speed of the
reaction increases.
Calderglen High School
Calderglen High School
2. Name FOUR factors which affect the speed (or rate) of a chemical reaction?
Particle Size (Surface Area)
Temperature
Concentration
Use of Catalyst
3. Work out the rate of reaction over the first 20 seconds.
Rate = Rate = Change in ConcentrationChange in Concentration
Change in TimeChange in Time
= = (0.2 – 0.05)(0.2 – 0.05)
(20 – 0)(20 – 0)
== 0.15 0.15 = 0.0075 mol /l / s = 0.0075 mol /l / s
2020
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mol
/ l
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4. Describe how particle size affects the speed of reaction?
As particle size decreases theAs particle size decreases the
speed of reaction increasesspeed of reaction increases
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5. Describe how temperature affects the speed of reaction?
As temperature increases the As temperature increases the speed of reaction increasesspeed of reaction increases
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7. What is a catalyst?
A substance which can speed up a reaction, but is not used up in the
reaction and can be recovered chemically unchanged
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8. Why does decreasing the particle size of reactants increase the
speed of reaction?
Smaller particles give a bigger surface area. This results in more collisions between reactants and
therefore faster reactions
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9. Work out the rate of reaction between 20 and 40 seconds.
Rate = Rate = Change in VolumeChange in Volume
Change in TimeChange in Time
= = (41 – 29)(41 – 29)
(40 – 20)(40 – 20)
== 12 12
2020
= 0.6 cm= 0.6 cm33 / s / s
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10.10. What must be controlled when What must be controlled when carrying out experiments to carrying out experiments to compare compare
speeds of reaction?speeds of reaction?
All variables other than the All variables other than the one being tested must be one being tested must be
kept the same in all kept the same in all experimentsexperiments
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11. What is a VARIABLE?
Any factor in an experiment Any factor in an experiment which can be changed or varied. which can be changed or varied. e.g. concentration or temperaturee.g. concentration or temperature
of the solution usedof the solution used
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12. Give everyday examples of uses of catalysts?
Transition metals in car catalytic converters.
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13. Rates Experiments
• Which two of the following experiments
could be used to find the effect of changing
the particle size?
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2M hydrochloric acid at 250C
2M hydrochloric acid at 250C
2g of large chalk lump
2g of small chalk lumps
A2M hydrochloric
acid at 150C
2g of small chalk lumps
B
C1M hydrochloric
acid at 250C
2g of small chalk lumps
Dansweranswer
Calderglen High School
14. Rates Experiments
• Which two of the following experiments
could be used to find the effect of changing
the concentration of the acid?
Calderglen High School
2M hydrochloric acid at 250C
2g of small chalk lumps
A2M hydrochloric
acid at 150C
2g of small chalk lumps
B
2M hydrochloric acid at 250C
2g of large chalk lump
C1M hydrochloric
acid at 250C
2g of small chalk lumps
Dansweranswer
Calderglen High School
15. Rates Experiments
• Which two of the following experiments
could be used to find the effect of changing
the temperature of the acid?
Calderglen High School
2M hydrochloric acid at 250C
2g of small chalk lumps
A2M hydrochloric
acid at 150C
2g of small chalk lumps
B
2M hydrochloric acid at 250C
2g of large chalk lump
C1M hydrochloric
acid at 250C
2g of small chalk lumps
Dansweranswer
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