Topic 2 - States of Matter and Mixtures

Question 1

What are the states of matter

Answer 1

Solid, liquid, gas

Question 2

The forces between particles in a solid are…. meaning the particles

Answer 2

Strong so the particles dont move from their positions.

Question 3

The particles energy levels in a solid are

Answer 3

Low

Question 4

Particles in a solid can

Answer 4

Vibrate if heated up which leads to the object expanding slightly.`

Question 5

The forces between particles in a liquid are….. meaning

Answer 5

Medium, meaning the particles can move freely but stay near eachother. This means it doesnt keep a shape.

Question 6

The particles energy levels in a liquid are

Answer 6

Medium: higher than solids but lower than gas

Question 7

The particles in a liquid are always

Answer 7

Moving with random motion and they move faster when its hotter. It expands slightly when hot.

Question 8

The forces between particles in a gas are….. meaning

Answer 8

There is no forces between the particles meaning thye move freely and travel in straight lines unless they collide.

Question 9

Gases interact in container by

Answer 9

Bouncing around and filling the whole container at whatever pressure needed. They bounce of the walls and exert a pressure on the walls.

Question 10

When gases get hotter they

Answer 10

Move faster. They either expand or increase in pressure

Question 11

Solid to liquid is called….. and occurs because

Answer 11

Melting. Due to the particles gaining enough energy and vibrating enough to weaken the forces and break free.

Question 12

Liquid to gas is called…. and occurs because

Answer 12

Evaporating. Due to more energy and vibrations, which allows the bond to be broken completely and the particles
to move freely.

Question 13

Solid to gas is called…. and occurs because

Answer 13

Sublimation. When the particles in a solid gain so much more energy than they had, so they break there bonds instantly and move freely as a gas.

Question 14

Gas to liquid is called… and occurs because

Answer 14

Condensation. Thye lose energy and stop vibrating as much, so that the intermolecular forces are reformed.

Question 15

Liquid to solid is called…. and occurs because

Answer 15

Freezing. More energy is lost and vibrations reduce more. This means the intermolecular forces are strong enough to rearrange the particles into a lattice.

Question 16

Difference between chemical and physical changes

Answer 16

Chemical changes happen during chemical reactions. It is when the bonds between atoms break and the atoms change places. The reactants are rearranged to form the products.
Chemical changes are much harder to reverse compared to physical changes.

Question 17

How to predict a subtances physical state based on melting and boiling point.

Answer 17

Before melting point = Solid

Between melting and boiling point=Liquid

After boiling point=Gas

Question 18

What does pure mean in chem

Answer 18

A substance completely made up of a single element or compound

Question 19

A mixture is

Answer 19

A substance with more than 1 compound or seperate elements present

Question 20

How to use melting and boiling points to determine purity

Answer 20

Pure substances have a sharp melting and boiling point whereas mixtures melt over a range of temperatures

Question 21

What substances are simple distillation used for

Answer 21

Seperating a liquid from a solution eg. sea water to get pure water

Question 22

Simple distillation steps

Answer 22

Have a distillation flask connected to a condenser to a beaker.
Put sample in distillation flask and heat up to the boiling point of the desired solution to seperate
It passes through the condenser and is collected at the beaker

Question 23

Whats fractional distillation used for

Answer 23

a mixture of solutions eg crude oil

Question 24

Fractional distillation steps

Answer 24

Put mixture in a flask and attach a fractionating column on top with the same set up as normal distillation with more collecting beakers.
Gradually heat the flask until a substance evaporates, then gradually increase for each subatnce

Question 25

What is filtration used for

Answer 25

An insoluble solid mixed with a liquid

Question 26

Filtration steps

Answer 26

Filter paper in a funnel voer a beaker. Run solution through funnel.

Question 27

Crystalisation use

Answer 27

Seperating a soluble solid from a solution

Question 28

Crystalisation steps

Answer 28

Put solution in an evaporating dish and heat gently until some water evaporates. Leave to crystlaise at room temp, and the salt will separate from the solution.

Question 29

What is chromotography used for

Answer 29

Seperating a mixture of soluble substances and identifying them

Question 30

Two phases of chromotography

Answer 30

Mobile phase, stationary phase

Question 31

Mobile phase is where

Answer 31

The molecules can move. This is always a liquid or gas

Question 32

Stationary phase is wherw

Answer 32

The molecules cant move. This is a solid or thick liquid.

Question 33

Paper chromotography steps

Answer 33

Stationary phase - Paper Mobile phase - Solvent Draw a pencil ine at the bottom of paper with a spot of the mixture on it. Put solvwent in a beaker and dip paper int oit without it touching the line. Put a watch glass on top of the beaker to prevent evaporation Solvent will move up paper with some of the substances in the mixture, which will seperate and get in the stationary phase at different times. Remove paper before the olvent reaches the top.

Question 34

The amount of time the molecules spend in the two phases of chromotography depens on

Answer 34

Their solubility Their attraction to the stationary phase.

Question 35

Molecules with high solubility will therefore end up.... on the paper

Answer 35

Higher

Question 36

What do you do if there are colourless chemicals on the chromatogram such as amino acidsq

Answer 36

Spray a locating agent

Question 37

What is the R value for a spot on a chromatogram

Answer 37

The ratio of the distance travelled by the solute to the solvent

Question 38

Rr =

Answer 38

Distance travelled by solute / Distance travelled by solvent

Question 39

A certain substance in a chromotography mixture can be identified by

Answer 39

Doing the same with a pure sample and comparing the R values.

Question 40

A pure substance when seperated in chromatography

Answer 40

Only gives one spot as all the molecules are the same solubility

Question 41

Simple distillation and chromatography for ink(core practical) steps

Answer 41

Use distillation and measure the boiling point of the solvent to figure out what it could be. Then paper chromotography could also be done using the ink as the mixture. Thus allows you to find which different dyes the ink has, and the R values can be compared to oreferwence values to identify them

Question 42

4 sources of water that can be purified for potable water

Answer 42

Surface water - lakes, rivers, resovoirs Ground water - Aquifers, water underground Waste water - Contaminated water by humans Sea water - From oceans

Question 43

Which is the purest water source

Answer 43

Ground water

Question 44

Water treatment plans to purify include

Answer 44

Filtration - A wire mesh screens out large objects, then gravel and sand beds filter out other solids Sedimentation - Iron sulfate or aluminium sulfate is added, so fine particles clump at the bottom Chlorination - Chlorine gas is bubbled through to kill harmful bacteria and microbes

Question 45

Sea water purifcation process

Answer 45

(Only in very dry countries)Distilled to get pure water. However it needs loads of energy so its very expensive.

Question 46

What type of water should chemical analysts use

Answer 46

Pure water/ deoionised water

Question 47

What is deionised water

Answer 47

Water that has had the ions in tap water removed(eg calcium, iron)