factors affecting rates

Question 1

5 factors

Answer 1

• temperature
• concentration
• pressure
• surface area
• catalyst

Question 2

activation energy definition

Answer 2

the minimum amount of energy required to start a reaction

Question 3

collision theory

Answer 3

chemical reactions can only occur when reacting particles collide with each other, and with sufficient energy

Question 4

increase in collision result


Answer 4

increase in rate of reaction

Question 5

describe how increasing temperature affects the rate

Answer 5

• increases rate
• temp increase means increase in kinetic energy
• means particles move faster
• so more frequent collisions
• more energy also means more of the collisions will have enough energy for the reaction

Question 6

describe how increasing concentration affects the rate

Answer 6

• rate increases as
• more concentrated means more particles in same volume
• so more collisions as there are more particles than can collide
• so more frequent successful collision, increasing rate

Question 7

describe how increasing pressure affects the rate

Answer 7

• increases rate
• same number of particles occupy smaller space
• so more frequent collisions as particles more tightly packed
• increasing rate

Question 8

describe how increasing surface area affects the rate

Answer 8

• increases rate
• bigger surface area means bigger surface area to volume ratio
• so for the same volume of the solid, the particles have more area to work on
• so more frequent successful collisions
• increasing rate

Question 9

describe how adding a catalyst affects the rate

Answer 9

• increases rate
• catalyst is a substance that speeds up a reaction without being used up itself
• work by decreasing the activation energy needed for the reaction to occur by providing an alternative pathway with a lower activation energy

Question 10

will the same catalyst work for each reaction?

Answer 10

no different reactions need different catalysts

Question 11

what is the rate of reaction determined by?


Answer 11

the frequency of successful collisions

Question 12

pattern between rate and 4 key factors

Answer 12

directly proportional

Question 13

concentration of solution doubles state effect on rate and why?

Answer 13

• double the amount of particles in the same volume of solution
• so double amount of collisions
• so more frequent successful collisions
• so increase rate

Question 14

pressure state

Answer 14

gas

Question 15

conc state

Answer 15

liquid

Question 16

surface area state

Answer 16

solid

Question 17

2 benefits of catalysts

Answer 17

• carry out reactions quickly without increasing temp, saving money
• aren’t used up in reaction so can be reused