Topic 1: Particles

Question 1

What are the three states of matter?

Answer 1

• Solid
• Liquid
• Gas

Question 2

Where do state changes occur?

Answer 2

Melting and Boiling Points

Question 3

What state changes occur at the melting point?

Answer 3

• Melting
• Freezing

Question 4

What state changes occur at the boiling point?

Answer 4

• Boiling
• Condensing

Question 5

What state change occurs at any temperature?

Answer 5

• Evaporation
• Maximum rate occurs at boiling point

Question 6

True or False: Individual Atoms and Bulk Matter share the same properties

Answer 6

False, individual atoms themselves do not share the same properties as bulk matter

Question 7

Describe the properties of a solid

Answer 7

• Regular Arrangement
• Vibrate about a fixed position
• Very closely packed

Question 8

Describe the properties of a liquid

Answer 8

• Randomly Arranged
• Move around each other
• Close

Question 9

Describe the properties of a gas

Answer 9

• Randomly arranged
• Move quickly in all directions
• Far Apart

Question 10

What is a physical change?

Answer 10

Change which doesn’t involve a change in the identity of the substance

Question 11

What is a chemical change?

Answer 11

• Also known as a chemical reaction
• Change in which one or more substances are converted into different substances

Question 12

What do you call the substance that react in a chemical change?

Answer 12

Reactants

Question 13

What do you call the substance that form in a chemical change?

Answer 13

Products

Question 14

What does a physical change usually involve?

Answer 14

Changes in force between the particles of the substances, but the particles and chemical properties remain the same

Question 15

True or False: Physical Changes are easy to reverse

Answer 15

True, no new substance is formed during interconversions of state making it easy

Question 16

What is the state change for melting?

Answer 16

Solid to liquid

Question 17

What is the state change for boiling?

Answer 17

Liquid to gas (from below surface and at surface)

Question 18

What is the state change for freezing?

Answer 18

Liquid to solid

Question 19

What is the state change for evaporation?

Answer 19

Liquid to gas (at surface only)

Question 20

What is the state change for condensation?

Answer 20

Gas to liquid

Question 21

What is the state change for sublimation?

Answer 21

Solid to gas

Question 22

What is the state change for deposition?

Answer 22

Gas to solid

Question 23

What does particle theory explain?

Answer 23

Particle theory explains how matter changes state based on the energy and forces between particles in a substance.

Question 24

What determines the energy needed to change a solid to a liquid or a liquid to a gas?

Answer 24

The energy required depends on the relative strength of the forces acting between the particles.

Question 25

How do stronger forces between particles affect melting and boiling?

Answer 25

The stronger the forces, the higher the energy needed for melting and boiling to occur.

Question 26

What happens to particles when a substance is heated?

Answer 26

Particles absorb thermal energy, which is converted into kinetic energy, causing them to move more

Question 27

What happens when a solid is heated?

Answer 27

The particles vibrate more, causing the solid to expand until the bonds break and the solid melts.

Question 28

What occurs when a liquid is heated further?

Answer 28

The liquid expands, and some particles at the surface gain enough energy to overcome intermolecular forces and evaporate.

Question 29

What happens at the boiling point of a liquid?

Answer 29

All particles gain enough energy to break intermolecular forces, and the liquid boils as molecules escape.

Question 30

What are limitations of the particle theory?

Answer 30

- Consider all particles, irrespective of state or chemical identity, as small, solid and inelastic - Fails to consider intermolecular forces - Fails to consider space between particles - Fails to consider difference caused by different particles

Question 31

What were the three key ideas in which John Dalton based his atomic theory on in 1803?

Answer 31

- Matter is made of atoms which are tiny particles that cannot be created, destroyed, or divided - Atoms of the same element are identical, and atoms of different elements are different - Different atoms combine together to form new substances

Question 32

Describe Thomson's Plum Pudding Model

Answer 32

- Discovered electron in 1897 - Used cathode-ray tube, identified electron as negatively charged subatomic particle, hence proving atoms are divisible - Proposed model, depicted electrons spread throughout positively charged material

Question 33

Describe Rutherford, Geiger and Marsden's Model

Answer 33

- Fired positively charged alpha particles at thin sheet of gold foil - Expected particles to pass through due to plum pudding model - Some particles scattered at large angles or bounced back - Rutherford proposed atoms have dense, positively charged nucleus containing most of atom's mass and a lot of empty space with electrons orbiting

Question 34

Describe The Bohr Model

Answer 34

- Proposed electrons orbit in fixed shells - Each shell had different energy with higher energy further away from nucleus - Solved why atom does not collapse inwards due to attraction between positive nucleus and negative electrons - Led to discovery of proton

Question 35

What is the size of an atom?

Answer 35

Radius of 1 x 10⁻¹⁰ metres

Question 36

What is the difference between radius of atom and nucleus?

Answer 36

- Radius of the nucleus is about 10 000 times smaller than that of the atom, so it is an extremely small region of space

Question 37

What is the relative charge and mass of a proton?

Answer 37

Charge: +1 Mass: 1

Question 38

What is the relative charge and mass of a neutron?

Answer 38

Charge: 0 Mass: 1

Question 39

What is the relative charge and mass of an electron?

Answer 39

Charge: -1 Mass: 1/1836

Question 40

What is the atomic number?

Answer 40

- Number of protons/electrons - Symbol is Z - Unique to element - Does not change in chemical reaction

Question 41

What is the mass number?

Answer 41

- Total number of protons and neutrons - Symbol is A - Collectively called nucleons

Question 42

What are isotopes?

Answer 42

- Atoms of same element that contain same number of protons but different number of neutrons - Same chemical characteristics as no. of electrons in shells don't change - Add mass only

Question 43

What are ions?

Answer 43

- Atom that has a positive or negative electrical charge - Happens when atom gain or lose electrons to become stable changing overall charge Loses electron: Cation Gains electron: Anion