Year 9 Science Chemistry

Question 1

What is meant by the rate of reaction?

Answer 1

how fast the reactants are converted into products

Question 2

Which of the following could you measure to find out the rate of reaction?

Answer 2

The volume of gas produced

Question 3

How do you know when the reaction between magnesium and hydrochloric acid is complete?

Answer 3

The magnesium is no longer visible because it has all reacted.

Question 4

Changing the temperature will affect the rate of the reaction between magnesium and hydrochloric acid. This is because

Answer 4

at higher temperatures the particles have more energy and are more likely to collide and react.

Question 5

What is the independent variable in how changing the temperature of the acid affects the time it takes for the reaction between magnesium and hydrochloric acid to complete.

Answer 5

The temperature of the acid

Question 6

What is the dependent variable in how changing the temperature of the acid affects the time it takes for the reaction between magnesium and hydrochloric acid to complete.

Answer 6

The time taken for the reaction to complete

Question 7

In an investigation, the independent variable is temperature of the acid. What would be the most suitable way to vary the temperature of the acid?

Answer 7

Use a water bath which is set to specific temperatures.

Question 8

What is the mean rate of reaction

Answer 8

volume of gas formed divided by the time taken

Question 9

Two investigations are set out, one with more concentration than the other, how would the line of best fit be different for the one with more concentration?

Answer 9

It would have a steeper slope.

Question 10

Sodium Carbonate (in the correct formulae)

Answer 10

SCO3

Question 11

Sodium Chloride (in the correct formulae)

Answer 11

S2Cl

Question 12

What is Collision Theory?

Answer 12

a chemical reaction can only occur between particles when they collide (hit each other)

Question 13

What can the rate of reaction depend on?

Answer 13

Temperature, Concentration, Particle Size and Catalysts

Question 14

What will speed up a chemical reaction?

Answer 14

Increasing temperature, Increasing the concentration and adding a catalyst.

Question 15

What will not speed up a chemical reaction?

Answer 15

Increasing the particle sizes.

Question 16

What’s the proper name for the Triangle Beaker?

Answer 16

A conical flask

Question 17

What’s the proper name for a tube with measurements on it?

Answer 17

A measuring cylinder

Question 18

What is better, Marbled Chips or Marbled Powder ( for a faster reaction)

Answer 18

The marbled powder because it had a larger surface area, giving more opportunities for collision to occur. With the collisions occurring more frequently and more room to travel across, it has been confirmed to be a faster rate of reaction.

Question 19

What is the formula for rate of reaction?

Answer 19

change in concentration/change in time

Question 20

What is a catalyst and how are they used?

Answer 20

A catalyst is a substance that can increase the rate of reaction without using itself up.

Question 21

What can catalysts provide?

Answer 21

Catalysts provide an alternative pathway with a lower Activation Energy.

Question 22

What does decreasing the activation energy mean?

Answer 22

It means that more particles will have sufficient energy to overcome the energy barrier and react.

Question 23

What happens during a reaction?

Answer 23

The energy rises to a maximum, then falls.

Question 24

What is activation energy?

Answer 24

the minimum energy required to cause a process (such as a chemical reaction) to occur.

Question 25

What is needed to overcome the activation energy?

Answer 25

At least the minimum amount of energy is required. Only reactants with energy equal to, or greater than, this value will react.

Question 26

If there is a higher concentration what is going to happen?

Answer 26

More Collisions

Question 27

If there is a lower concentration what is going to happen?

Answer 27

Less Collisions

Question 28

More frequent collisions come from…

Answer 28

• an increased particle speed
• more particles present

Question 29

How is
- an increased particle speed
and
- more particles present
achieved?

Answer 29

• A higher temperature
• A higher amount of mass

Question 30

More successful collisions come from…

Answer 30

• particles with more energy
• a lower activation energy

Question 31

How is
- particles with more energy
- a lower activation energy
achieved?

Answer 31

• A higher Temperature
• A use of a catalyst

Question 32

What is a control variable?

Answer 32

A variable that is kept the same during a scientific experiment

Question 33

What is a dependent variable?

Answer 33

A variable that changes as a result of the independent variable manipulation in experiments.

Question 34

What is an independent variable?

Answer 34

A variable you manipulate, control, or vary in an experimental study to explore its effects

Question 35

How do you use a tangent?

Answer 35

A tangent must first be drawn to the curve. Two lines should then be drawn down from two points along the tangent to the x-axis

Question 36

When are reactions at their fastest?

Answer 36

A reaction is at their fastest at the start because there is the most reactant particles so there is a high frequency of successful collisions