Qualitative And Quantitative Analysis

Question 1

What is qualitative analysis

Answer 1

Tell you what’s present

Question 2

What is quantitative analysis

Answer 2

How much of that substance is present

Question 3

How do you test for positive ions

Answer 3

Using sodium hydroxide to form an insoluble coloured hydroxide

Question 4

What colour precipitate does calcium form

Answer 4

White

Question 5

What colour does copper form

Answer 5

Blue

Question 6

What colour does iron (II) form

Answer 6

Green

Question 7

What colour does iron (III) form

Answer 7

Brown

Question 8

What colour does aluminium form

Answer 8

White at first but then redissolves in excess NaOH to give a colourless solution

Question 9

What does ammonium form

Answer 9

No precipitate but when heated gives off ammonia which can be identified by Turning universal indicator paper purple

Question 10

What is the test for halides

Answer 10

Add dilute nitric acid followed by silver nitrate

Question 11

Why is the acid added in a test for halides

Answer 11

To get rid of carbonate ions before testing

Question 12

What colour precipitate does chloride give

Answer 12

White

Question 13

What colour precipitate does bromide gives

Answer 13

Cream

Question 14

What colour does iodide give

Answer 14

Yellow

Question 15

How do you test for carbonates

Answer 15

Use dilute acid to form carbon dioxide and test with lime water

Question 16

How do you test for sulphates

Answer 16

Use Hydrochloric acid followed by barium chlorid to form am insoluble precipitate of barium sulfate

Question 17

What will one mole of any substance have a mass in grams equal to

Answer 17

The relative formula mass

Question 18

How do you work out the number of moles in a compound

Answer 18

Mass in grams divided by formula mass

Question 19

How do you work out the mass of an element or compound

Answer 19

Number of moles multiplied by relative formula mass

Question 20

How do you work out mass concentration of a solution

Answer 20

Mass divided by volume

Question 21

How do you work out mole concentration

Answer 21

Mass concentration divided by formula mass

Question 22

How do you work out mass concentration using mole concentration

Answer 22

Mole concentration multiplied by formula mass

Question 23

What does hard area react with soap to form

Answer 23

Scum

Question 24

What do you have to do to get a lather with hard water

Answer 24

Use more soap

Question 25

What is hardness in water caused by

Answer 25

Calcium and magnesium ions

Question 26

What does calcium carbonate react with acid rain to form

Answer 26

Calcium hydrogencarbonate

Question 27

How do you remove temporary hardness and what is it caused by

Answer 27

It's caused by calcium hydrogencarbonate | To remove it you can boil the water to from calcium carbonate (limescale)

Question 28

How can you remove permanent hardness

Answer 28

An ion exchange resin | Exchange of calcium and magnesium ions into sodium and hydrogen ions

Question 29

What is a resin

Answer 29

A solid polymer that's insoluble in water

Question 30

What are titrations used for

Answer 30

To find out concentrations

Question 31

What does titrations also allow you to find out

Answer 31

How much acid is needed to neutralise a quantity of alkali

Question 32

When is the indicator phenolphthalein used

Answer 32

When there is a weak acid and a strong alkali

Question 33

When is the indicator methyl orange used

Answer 33

Strong acid and weak alkali

Question 34

How do you work out the number of moles in a titration

Answer 34

Concentration multiplied by volume

Question 35

How would you make a soluble salt from an insoluble reactant

Answer 35

``` Acid plus insoluble reactant Insoluble reactant such as metal carbonate or oxide Add together and leave to dissolve Filter to remove excess solid Heat to from crystallised salt ```

Question 36

How do you make soluble salts from a soluble reactant

Answer 36

Acid with an alkali Alkali such as sodium ammonium or potassium hydroxide as they're soluble Must first carry out a titration to make sure the quantities are correct as you can't tell when the reaction has finished Add together and evaporate off to form a pure dry salt

Question 37

In what cases would you need to know what is present in a substance

Answer 37

Blood tests for general health,diagnose disease, alcohol | Water companies to check water purity

Question 38

Examples of insoluble bases

Answer 38

Metal carbonate | Metal oxide

Question 39

Examples of alkalis to produce a soluble reactant

Answer 39

Sodium , potassium, ammonium hydroxides

Question 40

When using an acid and a base to produce a soluble reactant why can't you add excess alkali to ensure the reaction has finished (been neutralised)

Answer 40

Because the salt produced is soluble so can't just filter out the excess