Chemistry analysis

Question 1

What is a pure substance

Answer 1

An element or compound not mixed with any other substance

Question 2

What is a formulation and how is it made?

Answer 2

A mixture that has been purposefully as a useful product
e.g medicines, alloys, cleaning agents

Question 3

How is Rf calculated?

Answer 3

Distance moved by the spot / distance moved by component

Question 4

What is flame spectrometry

Answer 4

The wavelengths of light emitted by metals ions when they are heated up

Question 5

What is the advantages of using instrumental methods?

Answer 5

They are very accurate
sensitive
and fast

Question 6

Why do scientists use flame emission spectrometry

Answer 6

Can show multiple ions present in a sample
and
The intensity of the lines show the concentration of the metal ion present

Question 7

What colour flame does lithum make?

Answer 7

Crimson red

Question 8

colour of sodium ions

Answer 8

Yellow

Question 9

Colours of K+ ions

Answer 9

lilac

Question 10

Colours of calcium ions

Answer 10

orange

Question 11

Colour of CU+ ions

Answer 11

blue/green

Question 12

What precipate is formed when NaOH reacts with a solution containing
Calcium
Magnesium
Aluminium ions

Answer 12

A white precipice is formed
However if extra NaOH is added to Aluminium it’s precipitate will dissolve

Question 13

compound colour formed when Iron ( III) is formed

Answer 13

brown

Question 13

Colour compound formed when copper reacts with NaoH?

Answer 13

A blue compund

Question 13

colour compound made with CL- with silver nitrate?

Answer 13

White precipitate

Question 14

compund colour made when iron ( II) reacts with NaOH

Answer 14

green

Question 14

Why is silver nitrate used when testing for halide precipiates?

Answer 14

Prevents any OH ions from reacting to with the silver as the nitrate removes any other ions

Question 14

colour compound made when BR- reacts with silver nitrate

Answer 14

very pale cream

Question 14

colour compound made when iodide reacts with silver nitrate?

Answer 14

Yellow precipitate

Question 15

How is sulphate ions tested?

Answer 15

a sample of so42- is tested with barium chloride

Question 16

How to differenatate between the Halide ion precipates?

Answer 16

Add dilute ammoina to Cl- and it will dissolve
add concentrated ammonia to Br- and it will dissolve

Question 17

why can we not add silver nitrate to Fluorine?

Answer 17

as F- doesnt form a precipatate.