Analysis, Purity and Separation Techniques

Question 1

Flame Test: Sodium

Answer 1

Yellow

Question 2

Flame Test: Potassium

Answer 2

Lilac

Question 3

Flame Test: Calcium

Answer 3

Orange

Question 4

Flame Test: Copper

Answer 4

Green

Question 5

Flame Test: Lithium

Answer 5

Crimson Red

Question 6

How do you do a flame test?

Answer 6

First have a wet splint. Then dip into the solution. Hold splint in a roaring flame(blue flame).

Question 7

Sodium Hydroxide: Aluminium

Answer 7

Colourless or clear

Question 8

Sodium Hydroxide: Magnesium

Answer 8

White

Question 9

Sodium Hydroxide: Calcium

Answer 9

White

Question 10

Sodium Hydroxide: Copper

Answer 10

Blue

Question 11

Sodium Hydroxide: Iron(II)

Answer 11

Green

Question 12

Sodium Hydroxide: Iron(III)

Answer 12

Orange-Brown

Question 13

How do you do a Sodium Hydroxide test?

Answer 13

Add Sodium Hydroxide to the solution. A colour change will happen if positive.

Question 14

How do you do a Carbonate test and what is the result?

Answer 14

Add acid to the solution. If it bubbles collect the gas and add it to the limewater. If the limewater is milky, Carbonates are present.

Question 15

How do you do a Sulphate test and what is the result?

Answer 15

Add Barium Chloride and a dilute Hydrochloric acid to the solution. If Sulphates are present, a white precipitate will form.

Question 16

What is the test for Halides and what is the result?

Answer 16

Add nitric acid and silver nitrate to the solution. The results are: Chlorine - White Bromine - Cream Iodine - Yellow

Question 17

What does pure mean?

Answer 17

A single element or compond not mixed with anything else.

Question 18

How do you find the Rf value?

Answer 18

Distance travelled by component Distance travelled by solvent

Question 19

How do you do paper chromatography?

Answer 19

Draw line at bottom of paper with pencilPut your food colouring/ink on the linePour water in the beaker until it’s under the lineLet inks separate into different colours

Question 20

How do you do thin layer chromatography?

Answer 20

Have a TLC plate coated with silica gelMark a line at the bottom of the plate with a pencilUse a capillary tube to place small spots on the lineFill glass jar with solvent until it’s under the linePlace TLC plate inside jar carefullySeal the jar so solvent doesn’t evaporate.

Question 21

What are the stationary and mobile phases in chromatography?

Answer 21

Mobile - The Solvent
Stationary - The paper or TLC plate

Question 22

What is the test for CO2?

Answer 22

Bubble CO2 through limewater. If it turns cloudy, CO2 is present.

Question 23

What is the test for Oxygen?

Answer 23

Place glowing splint inside testube with oxygen. If it’s present, the splint will relight.

Question 24

What is the test for Hydrogen?

Answer 24

Place a lighted splint inside a testube of hydrogen. If present, a squeaky pop will be heard.

Question 25

What is the test for Chlorine?

Answer 25

Use tap water to dampen litmus paper. Hold the paper near the chlorine. If it's present, the paper turns red the white.

Question 26

What is Filtration and describe the process

Answer 26

Filtration is used to remove an insoluble solid from a solution.First, grab a conical flask, filter paper and a funnel. Place the funnel in the flask and use the filter paper to make a shape of a cone. Pour the liquid on the filter paper. The solid with stay on the filter paper and the pure solution will pass through.

Question 27

What is Crystallisation and describe the process

Answer 27

Crystallisation is a process where a solid forms from a solution by heating or cooling. First place your solution in an evaporating basin. Let the solution heat all the solution. Soon, the liquid will evaporate. Finally, let it cool to see the crystals.

Question 28

What is Simple Distillation and describe the process

Answer 28

This is used to separate a liquid from a solution. First, we have a flask with the solution with a thermometer to check the temp. Then attach the condenser to the flask and place a beaker at the other end. Place a water jacket on the condenser. Place a bunsen burner under the flask. The solution will evaporate because of the heat. The gas travels through the condenser and turn into liquid. The liquid drips into the beaker.

Question 29

What is Fractional Distillation and describe the process

Answer 29

This is used to separate mixtures of liquids. First we need a fractionating column and a flask with a mixture. Place the fractionating column in the flask. Then start at the lowest boiling point of the solutins mixed and have a beaker to cellect. Once all the first solution is gone, do the same for the next until there is no solution remaining.