rates of reaction

Question 1

define fermentation

Answer 1

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

Question 2

define rate of reaction

Answer 2

how fast the reactants are changed into products

Question 3

define the collision theory

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?

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?

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?

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?

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

Answer 11

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