rates of reaction (paper 1)

Question 1

define fermentation (2)

Answer 1

• process in which ethanol is made from glucose and reacts in anaerobic conditions with the catalyst yeast to form ethanol and c02.
• Has to take place at 30 degrees so enzymes are at optimum temp.

Question 2

define rate of reaction

Answer 2

how fast the reactants are changed into products

Question 3

define the collision theory (2)

Answer 3

• more collisions there are = faster the reaction is
• particles must collide with enough energy to be succesful

Question 4

list the 4 factors that affect rates of reaction

Answer 4

temperature
pressure of a gas/ concentration of a solution
surface area
catalyst

Question 5

What happens when the temperature is increased? (4)

Answer 5

• particles move faster = more collisions
• increases energy of collisions
• this means that at higher temperatures there will be more successful collisions
• so increasing the temperature increases the rate of reaction

Question 6

what happens when the concentration is increased? (2)

Answer 6

• makes collisions more likely so reaction rate increases
• in a gas the frequency of collisions between particles will increase - so the rate of reaction will also increase

Question 7

what happens if the surface area is increased? (2)

Answer 7

• particles will have more area to work on so the frequency of collisions will increase
  -this means that the rate of reaction is faster for solids with a larger surface area to volume ratio

Question 8

define a catalyst

Answer 8

a substance which increases the rate of reaction without being chemically changed/used up in the reaction

Question 9

how do catalysts work and how is this done? (2)

Answer 9

• by decreasing the activation energy needed for a reaction to occur
• they do this by providing an alternative reaction pathway that has a lower activation energy

Question 10

how can the speed of a reaction be observed?

Answer 10

how quickly the reactants are used up

Question 11

describe how you can test to see if copper oxide is a better catalyst then manganese oxide (4)

Answer 11

• add manganese oxide to the water
• measure volume of gas produced at regular time intervals. record results in a table
• repeat experiment with same volume and concentration of hydrogen peroxide but using copper oxide as new catalyst
• if more gas is produced with copper oxide then it is a better catalyst