Standard Grade Chemistry - Topic 2

Front 1

Give 4 ways in which we can speed up a chemical reaction.

Back 1

1 - Change the particle size
2 - Change the concentration
3 - Change the temperature
4 - Using a catalyst

Front 2

Define:

Catalyst

Back 2

A substance which speeds up a chemical reaction but remains itself unchanged.

Front 3

Why does a car exhaust rust faster than the car body?

Back 3

Hot gases are going through the exhaust pipe, this speeds up rusting which is a chemical reaction.

Front 4

Why does food stored in a fridge stay fresher for longer than food stored at room temperature?

Back 4

The low temperature slows down the food decay which is a chemical reaction.

Front 5

Does sawdust burn faster or slower than logs? Explain.

Back 5

Sawdust burns faster than logs because the particles are smaller and smaller particles make the reaction go faster.

Front 6

Explain how changing the PARTICLE SIZE affects the speed of a reaction.

Back 6

Smaller particles speed up a reaction... the more surface area it has, the more area a reaction has to take place on it.

Hint 6

Whole potato -- SMALL surface area.
Quartered potato -- LARGE surface area.
(Clearly the quartered potato will cook faster than the whole potato).

Front 7

Explain how changing the CONCENTRATION affects the speed of a reaction.

Back 7

Using concentrated acid speeds the reaction up... as you increase the concentration you make the reaction faster.

Hint 7

Test tube 1 -- Powdered chalk + DILUTE acid.
Test tube 2 -- Powdered chalk + CONCENTRATED acid.
(Clearly test tube 2 will form bubbles of gas faster than test tube 1).

Front 8

Explain how changing the TEMPERATURE affects the speed of a reaction.

Back 8

When you increase the temperature, the reaction speeds up.

Hint 8

Experiment Temperature (°C)
20 | 30 | 40 | 50
(Clearly the experiment conducted at 50°C will occur at a greater speed than those of a cooler temperature).

Front 9

Explain how USING A CATALYST affects the speed of a reaction and give two benefits of using them.

Back 9

When you add a catalyst the reaction speeds up but the catalyst itself is NOT used up.
Benefit 1 -- Reduce the time taken for the experiment.
Benefit 2 -- Reduce the temperature it takes place at and saves energy.

Hint 9

(Catalyst = manganese peroxide)
Test tube 1 -- Hydrogen peroxide.
Test tube 2 -- Hydrogen peroxide + manganese dioxide.
(Test tube 1 will NOT relight a glowing splint as oxygen is produced very slowly, whereas test tube 2 WILL relight it as oxygen is produced much faster.

Front 10

What is the name given to reactions that take place inside your body without using a chemical catalyst?
Give BOTH terms.

Back 10

Biological catalysts.
These are called ENZYMES.

Front 11

Give 3 examples of everyday catalysts.

Back 11

Platinum -- For catalytic converter in cars.
Nickel -- To make margarine.
Iron -- To make ammonia.

Hint 11

NOTE: All the catalysts are Transition metals (between groups 2 & 3 on the Periodic Table <p.8 of data booklet>)