Particles & Mixtures

Question 1

Describe a Solid

Answer 1

• Strong force of attraction
• Close together
• Fixed position forming regular lattice arrangement
• Particles vibrate in position
• Hotter = Vibrate more = Solid expands slightly

Question 2

Describe a Liquid

Answer 2

• Weak force of attraction
• Randomly arrangened
• Free to move
• Particles constantly moving with random motion
• Hotter = faster they move = liquid expands slightly

Question 3

Describe a gas

Answer 3

• Very weak force of attraction
• Far apart and free to move
• Travel in straight lines
• Particles constantly moving with random motion
• Hotter = faster they move = gasses either expand or pressure increases

Question 4

Liquid to Gas =

Answer 4

Evaporation

Question 5

Gas to Liquid =

Answer 5

Condensation

Question 6

Solid to Gas =

Answer 6

Sublimation

Question 7

Solid to Liquid =

Answer 7

Melting

Question 8

Liquid to Solid =

Answer 8

Freezing

Question 9

What gas does Aqueous ammonia (NH3) give off

Answer 9

Ammonia gas

Question 10

What gas does Hydrochloric acid (HCL) give off

Answer 10

Hydrogen Chloride gas

Question 11

Describe experiment between Ammonia and Hydrogen Chloride

Answer 11

• White right of ammonium chloride form in glass tube
• Ammonia diffuses from one end of tube and hydrochloric acid diffuses from the other
• When meet they react to form Ammonium Chloride
• Ring forms nearest end of tube where hydrochloric acid was because particles of ammonia are smaller and lighter than particles of hydrogen chloride, so diffuse through air more quickly

Question 12

What colour is Bromine gas and what do you use it for

Answer 12

• Brown

* Used to demonstrate diffusion of gases

Question 13

Describe the experiment for Bromine gas and air

Answer 13

• Fill half glass jar w/ bromine gas and other half with air
• Separate glasses with glass plate
• When remove glass plate, brown bromine gas slowly diffuses through air
• Random motion of particles = Bromine will eventually diffuse right through air

Question 14

Define a Solution

Answer 14

Mixture of a solute and solvent that doesn’t separate out

Question 15

Define a Solute

Answer 15

Substance being dissolved

Question 16

Define a Solvent

Answer 16

Liquid it’s dissolving into

Question 17

Define a Saturated Solution

Answer 17

Solution where maximum amount of solute has been dissolved, no more solute will dissolve in solution

Question 18

How is the solubility of Ammonium Chloride affected by temperature

Answer 18

• Add excess ammonium chloride to water in a boiling tube to get a saturated solution
• Stir, place boiling tube in water bath
• After 5 mins check solution has reached 25 degrees
• Weigh Emory evaporating basin, pour some solution in basin
• Reweigh basin and contents
• Repeat experiment at different temperatures and work out solubility at each temperature

Question 19

How to calculate the Solubility

Answer 19

Solubility = Mass of solid / Mass of Water ( multiplied by 100)

Question 20

What is the Relative Mass and Charge of a Proton?

Answer 20

• Mass = 1

* Charge = +1

Question 21

What is the Relative Mass and Charge of a Neutron?

Answer 21

• Mass = 1

* Charge = 0

Question 22

What is the Relative Mass and Charge of an Electron?

Answer 22

• Mass = 0.0005

* Charge = -1

Question 23

What is the Nucleus?

Answer 23

• Middle of atom
• Contains protons and neutrons
• Positive charge

Question 24

What are the Electrons?

Answer 24

•Move around nucleus in shells

Question 25

What is the Mass Number?

Answer 25

Number above the element symbol

Question 26

What is the Atomic Number?

Answer 26

The number below the element symbol

Question 27

What is the Definition of Isotopes?

Answer 27

Same number of protons but different number of neutrons

Question 28

Define a Compound:

Answer 28

* Substance made up of two or more different elements which are chemically bonded together * Difficult to separate

Question 29

What does it mean if something is Pure?

Answer 29

Made up of a single element or compound

Question 30

What is Crystallisation used for?

Answer 30

To separate a Soluble Solid from a Solution

Question 31

Describe the test for Crystallisation:

Answer 31

* Place solution in evaporating basin and heat solution so it will get more concentrated and solvent can evaporate * Leave solution for week so crystals can form in a dry area * Filter crystals so left on filter paper * Obtain sample and dry by leaving by window seal

Question 32

What is Filtration used for?

Answer 32

Separate an insoluble solid from a liquid

Question 33

What is Chromatography used for?

Answer 33

To separate out dyes

Question 34

How does Chromatography separate mixtures?

Answer 34

* Different dyes move up paper at different rates * Some stick to paper and some dissolve in solvent * Distance dyes travel depends on solvent and paper

Question 35

What is the experiment for Chromatography?

Answer 35

* Draw baseline at bottom of filter paper using a pencil (insoluble) * Add spots of different ink to line * Role sheet up loosely and place in a beaker of solvent * Place lid on top of container so solvent doesn’t evaporate * Each dye move up paper at different rate and form spot in different places * When solvent nearly at top, take paper out and dry

Question 36

How do you calculate the Rf value for each chemical in Chromatography?

Answer 36

Distance travelled by solute / distance travelled by solvent

Question 37

What is Simple Distillation used for?

Answer 37

To separate out solutions

Question 38

What is Fractional Distillation used for?

Answer 38

To separate a mixture of liquids

Question 39

Describe a test for Simple Distillation:

Answer 39

* Solution heated, solution with lowest boiling point evaporates * Vapour cooled, condenses (into liquid), collected * Rest of solution left in flask * E.g. Pure water from sea water

Question 40

Describe a test for Fractional Distillation:

Answer 40

* Mixture In flask w/ fractionating column on top,heat it * Liquids evaporate at different temperatures because of different Bpt * When temp of thermometer matches Bpt of liquid w/ lowest boiling point (Bpt) it will reach top of column * Condense and go towards flask because column is cool at top * When this liquid is collected, raise temp until next one reaches top