Chemistry

Question 1

State the 5 statements that make up the Particle Theory of Matter.

Answer 1

1) All matter is made up of tiny particles, known as atoms.
2) Particles of matter are constantly in motion.
3) The space between particles are large compared to the particles themselves.
4) All particles of one substance are the same, different substances are made of different particles.
5) There are attracting forces among particles. The closer these particles are to each other, the stronger these forces become.

Question 2

Use the particles theory of matter to explain the following behaviour:
A piece of ice melts into water on a warm, sunny day.

Answer 2

The ice particles gather heat energy from the warm air. Therefore, when the ice is heated the particles move faster and break apart because they gain energy. Resulting in the ice melting into water.

Question 3

State the 5 methods of identifying a chemical change has occured.

Answer 3

1) A new colour has appeared.
2) There is a change of odour.
3) Bubbles or gas has formed.
4) Formation of precipitation (solid.)
5) Temperature change or production of light.

Question 4

Whats the difference between a chemical change and a physical change.

Answer 4

A physical change is when the characteristic physical properties of a substance do not change and no new substances are formed. Whereas, a chemical change is when a new substance is formed and has new properties that are different from those of the original substance.

Question 5

How do you find protons, neutrons, and electrons?

Answer 5

1) Protons = The atomic number.
2) Neutrons = Atomic mass - Atomic number
3) Electrons = The same as the number of protons.

Question 6

Complete the following table concerning the subatomic particles of the atom.

Answer 6

Subatomic particle. Mass. Charge. Location in the atom
Protons. 1 amu Positive Nucleus
Neutrons. 1 amu. Neutral Nucleus
Electrons. 0.0005 amu Negative Orbits/shells

Question 7

State where the following is a chemical or physical change:
1) Mixing salt and pepper
2) Evaporation of water
3) Cutting a marshmallow
4) Toasting a marshmallow
5) Burning magnesium.
6) Demolishing a car
7) The rusting of iron
8) Melting of sugar
9)) Baking a cake

Answer 7

1) Mixing salt and pepper - Physical change
2) Evaporation of water - Physical change
3) Cutting a marshmallow - Physical change
4) Toasting a marshmallow - Chemical change
5) Burning magnesium - Chemical change
6) Demolishing a car - Physical change
7) The rusting of iron - Chemical change
8) Melting of sugar - Physical change
9)) Baking a cake - Chemical change