The particulate nature of matter

Question 1

Matter

Answer 1

Matter is a substance that has mass and occupies space. All living and non-living things are matter

Question 2

Solids

Answer 2

Fixed shape, Fixed volume, Cannot be compressed

Particles are very closely packed together, orderly arrangement with fixed positions, particles can only vibrate/rotate about their fixed positions

Question 3

Liquids

Answer 3

No fixed shape, takes the shape of the container, fixed volume, cannot be compressed

Particles are closely packed together but not as close as those in solids, not orderly with no fixed position, particles can slide around one another

Question 4

Gas

Answer 4

No fixed shape, takes the shape of the container, no fixed volume, can be compressed

Particles are far apart, particles are in random arrangement, particles can move about freely in any direction at high speeds, occupying any available space

Question 5

What other states of matter exist other than solids, liquids and gases?

Answer 5

Plasma

Question 6

Kinetic Particle Theory

Answer 6

The kinetic particle theory states that all matter is made up of tiny particles and that these particles are in continuous random motion

All matter is made up of tiny particles
Spaces exist between the particles, which vary between the different states
Particles are always in continuous random motion. The particles move at different speeds in solids, liquids and gases

Question 7

Diffusion

Answer 7

The process in which particles move freely and randomly in a continuous manner to fill up any available space
Simple diffusion occur mainly in liquids and gases. Vacancy diffusion or interstitial diffusion occurs mainly in solids such as metals and alloys

Question 8

Factors affecting diffusion

Answer 8

Temperature - when temperature increases, particles have more kinetic energy and move faster, leading to a faster rate of diffusion. When temperature decreases, particles have less kinetic energy and move slower, leading to a slower rate of diffusion
( the higher the temperature, the faster the rate of diffusion )

Molecular mass of particles - the rate at which a gas diffuses depends upon its relative molecular mass. The greater the relative molecular mass, the slower the particles move and the slower the rate of diffusion. The smaller the relative molecular mass, the faster the particles move and the faster the rate of diffusion

Question 9

Melting ( solid -> liquid )

Answer 9

Particles in the solid vibrate and move faster when heated as they gain kinetic energy, until they have sufficient energy to overcome the forces of attraction holding them in their fixed positions. The particles eventually break away from their fixed positions and move around one another randomly. Temperature changes during melting: increase until melting point reached, remains constant during melting , continue to increase after it has melted

Question 10

Freezing ( liquids -> solid )

Answer 10

Particles in the liquid slows down and kinetic energy decreases, as energy is lost to the surroundings as heat when the liquid is cooled. The particles eventually settle into their fixed positions in an orderly arrangement, forming a solid. Temperature changes during freezing: decrease until freezing point, remains constant during boiling, continue to increase after it has become a gas

Question 11

Boiling

Answer 11

Particles in a liquid move faster when heated as they gain kinetic energy, until they have sufficient energy to completely overcome the forces of attraction holding them together. The particles become far apart from each other, moving freely and randomly in all directions, forming a gas. Temperature changes during boiling: increase until boiling point, remains constant during boiling, continue to increase after it has become a gas

Question 12

Evaporation

Answer 12

Process by which a liquid changes to a gas at temperatures lower than its boiling point

it occurs at all temperatures, and only at the surface of the liquid when some particles have enough energy to escape as a gas

Question 13

Volatile liquids

Answer 13

Evaporate very quickly at room temperature. They usually have boiling points just above the room temperature

Question 14

Differences between evaporation and boiling

Answer 14

Evaporation: Occurs only on the surface of the liquid, Occurs at all temperatures, a slow process

Boiling: Occurs throughout the entire liquid, occurs only at boiling point, a fast process

Question 15

Condensation

Answer 15

Process by which a gas changes to a liquid

Condensation occurs when water vapour touches a cold surface
When the temperature drops, gas particles lose kinetic energy, move more slowly and eventually becomes closer together, changing into a liquid

Question 16

Sublimation

Answer 16

Process by which a solid changes directly to a gas without going through the liquid state is called Sublimation

The particles at the surface of the solid have enough energy to break away from the solid and escape as a gas

Question 17

Atoms

Answer 17

Atoms are made up of protons, neutrons and electrons called subatomic particles

Question 18

The ___ the electron shell is from the nucleus, the higher its energy level and the less stable the electrons will be

Answer 18

further

Question 19

The ___ the electron shell is from the nucleus, the higher its energy level and the less stable the electrons will be

Answer 19

further

Question 20

Isotopes

Answer 20

Isotopes of the same element have the same number of protons but different number of neutrons

Question 21

Uses of isotopes

Answer 21

Some isotopes can emit high-energy radiation that can damage living cells. These isotopes are radioactive substances called radioisotopes. However, when handled safely and carefully, these isotopes can be useful

Question 22

Relative atomic mass formula

Answer 22

Relative atomic mass = ( relative abundance of isotope 1 x atomic mass of isotope 1 ) + ( relative abundance of isotope 2 x atomic mass of isotope 2 ) + …

Relative abundance refer to the percentage of the isotope present on Earth

Question 23

Why do atoms lose or gain electrons?

Answer 23

Atoms lose or gain electrons to attain a stable electronic configuration of a noble gas

Question 24

Ionic bond

Answer 24

An ionic bond is the strong electrostatic forces of attraction between the positively charged cation and the negatively charged anion in a compound

Question 25

Explain why the lattice structure of sodium chloride causes the crystals to be very hard and have regular shapes?

Answer 25

Sodium chloride has a giant ionic crystal lattice structure. Each sodium cation and chloride anion is held together due to strong electrostatic forces of attraction between oppositely charged ions in the giant ionic crystal lattice structure. Hence, the sodium chloride crystals are very hard as large amount of heat energy is taken in to overcome the strong electrostatic forces of attraction between the oppositely charged ions. The sodium chloride crystals have regular shapes as the sodium ions and chloride ions are held in fixed positions in a 3 dimensional giant crystal lattice

Question 26

Volatility of ionic compounds

Answer 26

The giant ionic crystal lattice structure of an ionic compound is held together by strong ionic bonds between the oppositely charged ions. Hence, an ionic compound cannot be easily evaporated. As a result, ionic compounds are solids at room temperature and pressure and have no smell

Question 27

Melting and boiling points of ionic compounds

Answer 27

Sodium chloride is an ionic compound with a giant ionic crystal lattice structure. Each sodium cation and chloride anion is held together by strong electrostatic forces of attraction between oppositely charged ions. Large amount of heat energy is taken in to overcome the strong electrostatic forces of attraction between the oppositely charged ions. As a result, sodium chloride has high melting point

Question 28

Solubility

Answer 28

Most ionic compounds are usually soluble in water. Ionic compounds are insoluble in organic solvents

There is an attraction between the cations/anions and the water molecules. Hence, this causes the ions to separate and go into the solution ( soluble )

Question 29

Organic solvents

Answer 29

Ethanol, petrol and turpentine

Question 30

Electrical conductivity of ionic compounds ( in solid state )

Answer 30

In the solid state, the ions in the ionic compound are solid ions and cannot move because they are held together by very strong electrostatic forces of attraction in the giant ionic crystal lattice. Hence, the ions are not able to carry the negative electric charge during conduction. Hence, solid ionic compounds do not conduct electricity