Chem

Question 1

Matter

Answer 1

Anything that has mass and takes up volume/space

Question 2

Diffusion

Answer 2

The process of movement of particles from a high concentration area to a low concentration area to form an equilibrium

Question 3

How does perfume liquid perform diffusion?

Answer 3

The liquid from the perfume spreads into the air, the liquid perfume has a higher concentration of particles than the air around and hence the particles move around until they reach equilibrium

Question 4

2 factors affecting the rate of diffusion

Answer 4

Temperature - Higher temperature means higher kinetic energy, which makes the particles move faster and collide more frequently

Molecular Mass - Heavier molecules diffuse slower due to lower kinetic energy, while lighter molecules diffuse faster due to their lower molecular mass, Hydrogen gas (H2) has a molecular mass of 2 g/mol and diffuses faster than oxygen gas (O2) with a molecular mass of 32 g/mol.

Question 5

solute

Answer 5

the substance which is being dissolved

Question 6

Solvent

Answer 6

The liquid that is doing the dissolving (can sometimes be a gas as well)

Question 7

concentration

Answer 7

Amount of particles in an area

Question 8

Element

Answer 8

a chemical substance that cannot be broken down into other substances, composed of protons, neutrons and electrons, eg - Hydrogen

Question 9

Mixture

Answer 9

Made of 2 or more substances that have been physically combined, can be separated using physical means, eg - soup

Question 10

compound

Answer 10

two or more elements that have been chemically combined in a fixed ratio, eg - Water (H2O)

Question 11

Pure substance

Answer 11

composed of a single element/compound and has a fixed and definite composition, eg - Iron

Question 12

How to check if a substance is pure or not?

Answer 12

A pure substance has a constant and fixed melting point and boiling point, while an impure substance has a lower and broader melting point and a higher and broader boiling point

Question 13

Homogenous mixture

Answer 13

Particles are distributed evenly and have a uniform composition

Question 14

Heterogenous Mixture

Answer 14

Components are mixed and can easily be identified. Has a non-uniform composition

Question 15

Element, mixture or compound - Zinc

Answer 15

Element

Question 16

Element, mixture or compound - Saltwater

Answer 16

Mixture

Question 17

Element, mixture or compound - Sugar Syrup

Answer 17

Mixture

Question 18

Element, mixture or compound - Marble Chips

Answer 18

Compound

Question 19

Element, mixture or compound - Aluminium

Answer 19

Element

Question 20

States of Matter

Answer 20

Solid, Liquid and Gas

Question 21

Properties of Solid

Answer 21

Particles are closely packed together and vibrate off each other, with definite shapes, High density and incompressible. Intermolecular space is less

Question 22

Properties of liquid

Answer 22

Particles move freely, and medium kinetic energy, definite volume but no shape (takes the shape of a container), not compressible. Intermolecular space is more than solid but less than gas

Question 23

Properties of gas

Answer 23

Particles roam around freely at high speeds, with no fixed volume and no fixed shape, compressible, low-density. Very high intermolecular space

Question 24

Kinetic Theory of Matter

Answer 24

States that all matter is made of tiny particles (atoms) that are always moving

Question 25

What are Heating and Cooling Curve

Answer 25

A simple line graph that shows the phase change a given substance undergoes with increase/decrease in temp

Question 26

What are solutions

Answer 26

Homogenous mixtures which contain small solute particles in a solvent, eg - sugar in water

Question 27

What are Suspensions

Answer 27

Heterogenous mixtures in which small particles of a solid remain suspended from a liquid/gas, eg - muddy water

Question 28

What are colloids

Answer 28

Heteregrnous mixture made of 2 phases. The dispersed phase and the dispersion medium. They are mixtures where tiny particles are spread out but don't settle, eg - milk powder and water mixture

Question 29

Rank colloids, suspensions and solutions based on particle size (biggest to smallest)

Answer 29

1. Suspensions 2. Colloids 3. Solutions

Question 30

What are emulsions

Answer 30

Liquid + Liquid mixtures which are immiscible (not forming a homogeneous mixture when mixed) or are partly miscible, eg - Mayo, paint, egg yolks

Question 31

What are the 6 main methods of separation of mixtures?

Answer 31

1. Filtration 2. Evaporation 3. Simple Distillation 4. Fractional Distillation 5. crystallization 6. chromatography

Question 32

What is Chromatography

Answer 32

a technique for the separation of a mixture by passing it in solution in which the components move at different rates.

Question 33

What is Paper Chromatography

Answer 33

The experiment uses to ink to see how it distributes on chromatographic paper

Question 34

Does the solute travel more or the solvent, in chromatography

Answer 34

solute

Question 35

Explain the stationary phase in chromatography

Answer 35

The stationary phase is that substance which does not move. Usually a solid but in paper chromatography, it can be a liquid as well

Question 36

Explain the mobile phase in chromatography

Answer 36

The phase where the substance moves down the column and into the stationary phase.

Question 37

What is Rf value?

Answer 37

is a ratio used to describe the distance a component in a mixture travels in relation to the distance the solvent travels

Question 38

How to calculate Rf value

Answer 38

distance travelled by solute (stationary phase)/ Distance travelled by solvent

Question 39

List some everyday uses of Chromatography

Answer 39

Forensic science Creating Vaccines, Food and Beverage Testing Drug testing

Question 40

What is Filtration

Answer 40

Used to separate solid from liquid. It is done with filter paper or a funnel Eg - Getting chalk residue from chalk and water mixture

Question 41

What is evaporation

Answer 41

Used to separate a solid from a solution it has been dissolved in. The solution is heated so that the liquid is evaporated and only the solid remains

Question 42

What is Crystallization

Answer 42

separates solid from a solution by turning the mixture into crystals, then the crystals are left to dry. The remaining parts are the residue of the solid

Question 43

What is simple distillation and what are its steps

Answer 43

Used to get the solvent from a solution Steps: 1. Impure substance is heated 2. It boils and steam rises and condenses in condenser 3. Impurities are left behind 4. Steam condenses into the pure liquid and drops into the beaker

Question 44

What is Fractional Distillation and what is its steps

Answer 44

Used to separate liquid from each other Steps: 1 Mixture is heated 2. Wanted substance evaporates into the column 3. It then condenses in the beads in the column causing the beads to heat 4. When the beads reach a certain temp. (when the liquid stops condensing), wanted substance will heat and rise while the unwanted travels through the condenser and drops on the beaker.

Question 45

Real-world uses of fractional distillation

Answer 45

purification of water separating ethanol and water. Separating crude oil into petroleum, diesel, etc.