Year 8 Chemistry Test

Question 1

What is a catalyst?

Answer 1

A chemical that can speed up chemical change.

Question 2

How can a reaction rate be increased? (Name at least two things from the list)

Answer 2

• by increasing the amount of reactants that are combined.
• by increasing the concentration of the reactants.
• by increasing the surface area of the reactants.
• by increasing the temperature of the reaction.
• by increasing the pressure that the reaction occurs at.

Question 3

Which of the 3 types of states (solid liquid gas) is the most compressible and why?

Answer 3

Gas because there is a lot of space between the particles that can be compressed.

Question 4

Describe all the ways that a physical change can be distinguished from a chemical change…

Answer 4

Physical - change of state, shape & size

Chemical - change in colour

Question 5

What is the charge of a Neutron?

Answer 5

Neutral.

Question 6

What is the charge of an electron?

Answer 6

Negative.

Question 7

What is the charge of a proton?

Answer 7

Positive.

Question 8

Te atomic number is found by…

Answer 8

The number of protons.

Question 9

The mass number is found by…

Answer 9

Protons and neutrons.

Question 10

The area in which the electrons exist is called the…

Answer 10

Neutron cloud.

Question 11

The area in which the protons and neutrons exist is called the….

Answer 11

Nucleus.

Question 12

What is the meaning of element?

Answer 12

One type of atom, pure substance.

Question 13

What is the meaning of atom?

Answer 13

Smallest part of matter.

Question 14

There are four main factors that effect the rate of reaction. These are…

Answer 14

• concentration
• collisions
• surface area
• temperature
• frequency
• efficient
• activation
• catalyst
• unchanged
• energy

Question 15

Compare a physical and a chemical change. Is a new product produced?

Answer 15

Yes. A physical reaction would change shape/size but a chemical may change temperature/colour, etc.

Question 16

Compare a physical and chemical change. Are the reactant atoms changed?

Answer 16

Yes, for chemical.

Question 17

Compare a physical and chemical change. Can a change of state occur?

Answer 17

Yes, for physical.

Question 18

Compare a physical and a chemical change. Can a colour change occur?

Answer 18

Yes, for chemical. But also sometimes physical.

Question 19

If a gas is heated in a balloon, what will occur? What will be observed?

Answer 19

There will be a physical change that will occur because there will be a change in shape (expand/bigger) and also there would be more atoms inside of the balloon.

Question 20

Explain why mixing is a physical change. Why is it still possible for colour changes to occur?

Answer 20

Because the mixing is not a chemical change. Colour change occurs because the mixing may dilute some of the colour. Eg: cordial in water.

Question 21

Which of the 3 types of states is the most compressible and why?

Answer 21

Gas, because there is a lot of space between the particles that can be compressed.

Question 22

Describe a metalloid.

Answer 22

A non-metallic element.

Question 23

What are the non-metals in the periodic table?

Answer 23

(Total is 19, only told to go up to a certain number) helium, carbon, nitrogen, oxygen, fluorine, neon, phosphorus, Sulfur, chlorine, argon, selenium, bromine, krypton.

Question 24

What is an important thing to remember about the periodic table?

Answer 24

Periods go across the table.