1rates of reactions

Question 1

method to investigate the effect of surface area of a solid on the rate of reaction

Answer 1

Add dilute hydrochloric acid to the conical flask
Use a delivery tube to connect this flask to an inverted measuring cylinder upside down in a water trough
Add calcium carbonate chips into the conical flask and close the bung
Measure the volume of gas produced in a fixed time using the measuring cylinder
Repeat with different sizes of calcium carbonate chips

Question 2

method to investigate the effect of concentration of a solution on the rate of reaction

Answer 2

Measure 50 cm3 of sodium thiosulfate solution into a flask
Measure 5 cm3 of dilute hydrochloric acid into a measuring cylinder
Draw a cross on a piece of paper and put it underneath the flask
Add the acid into the flask and immediately start the stopwatch
Look down at the cross from above and stop the stopwatch when the cross can no longer be seen
Repeat using different concentrations of sodium thiosulfate solution (mix different volumes of sodium thiosulfate solution with water to dilute it)

Question 3

results of investigating the effect of concentration of a solution on the rate of reaction

Answer 3

With an increase in the concentration of a solution, the rate of reaction will increase
This is because there will be more reactant particles in a given volume, allowing more frequent and successful collisions, increasing the rate of reaction

Question 4

method to investigate the effect of temperature on the rate of reaction

Answer 4

Dilute hydrochloric acid is heated to a set temperature using a water bath
Add the dilute hydrochloric acid into a conical flask
Add a strip of magnesium and start the stopwatch
Stop the time when the magnesium fully dissolves
Repeat at different temperatures and compare results
Result:

Question 5

results of investigating the effect of temperature on the rate of reaction

Answer 5

With an increase in the temperature, the rate of reaction will increase
This is because the particles will have more kinetic energy than the required activation energy, therefore more frequent and successful collisions will occur, increasing the rate of reaction

Question 6

method to investigate the effect of a catalyst on the rate of reaction

Answer 6

Add hydrogen peroxide into a conical flask
Use a delivery tube to connect this flask to a measuring cylinder upside down in water trough
Add the catalyst manganese(IV) oxide into the conical flask and close the bung
Measure the volume of gas produced in a fixed time using the measuring cylinder
Repeat experiment without the catalyst of manganese(IV) oxide and compare results

Question 7

factors affecting rate

Answer 7

Concentration of the reactants in solution
Temperature at which the reaction is carried out
Surface area of solid reactants
The use of a catalyst

Question 8

concentration of a solution affect on rate

Answer 8

Increasing the concentration of a solution will increase the rate of reaction
This is because there will be more reactant particles in a given volume, allowing more frequent and successful collisions per second
If you double the number of particles you will double the number of collisions per second
The number of collisions is proportional to the number of particles present

Question 9

temperature affect on rate

Answer 9

Increase in the temperature, the rate of reaction will increase
This is because the particles will have more kinetic energy than the required activation energy, therefore there will be more frequent and successful collisions per second, increasing the rate of reaction
The effect of temperature on collisions is not so straight forward as concentration or surface area; a small increase in temperature causes a large increase in rate

Question 10

surface area affect on rate

Answer 10

With an increase in the surface area of a solid reactant, the rate of reaction will increase
This is because more surface area of the particles will be exposed to the other reactant, producing a higher number of collisions per second
If you double the surface area you will double the number of collisions per second

Question 11

catalysts are

Answer 11

substances which speed up the rate of reactions without themselves being altered or consumed in the reaction

Question 12

the mass of a catalyst

Answer 12

at the beginning and end of a reaction is the same and they do not form part of the equation

Question 13

catalysts work by

Answer 13

providing an alternate route for the reaction to occur- they do this by lowering the activation energy required so they provide a reaction pathway requiring less energy

Question 14

method to investigate effect of surface area on rate of reaction- marble chips experiment

Answer 14

Add hydrochloric acid into a conical flask
Use a delivery tube to connect this flask to an inverted measuring cylinder
Add marble chips into the conical flask and close the bung
Measure the volume of gas produced in a fixed time using the measuring cylinder
Repeat with different sizes of marble chips / concentrations of hydrochloric acid

Question 15

result of investigating effect of surface area on rate of reaction- marble chips experiment

Answer 15

Increase in the surface area of the marble chip, the rate of reaction will increase
This is because more surface area particles of the marble chips will be exposed to the dilute hydrochloric acid so there will be more frequent and successful collisions, increasing the rate of reaction

Question 16

method to investigate the effect of catalysts on rate of reaction

Answer 16

Add hydrogen peroxide into a conical flask
Use a delivery tube to connect this flask to a measuring cylinder upside down in water trough
Add the chosen catalyst into the conical flask and close the bung
Measure the volume of gas produced in a fixed time using the measuring cylinder
Repeat experiment with different catalysts and compare results
Catalysts to try could include: manganese(IV) oxide, lead(II) oxide, iron(III) oxide and copper(II) oxide

Question 17

results of investigating the effect of catalysts in rate of reaction

Answer 17

the data for different catalysts can be plotted on the same graphs and the relative rates compared