Tests For Anions

Question 1

What is testing for Anions

Answer 1

Test for some common negative ions

Question 2

What are carbonates

Answer 2

Substance that contains CO3*2- ions

Question 3

How do you detect carbonates

Answer 3

Use a dropping pipette to a add a few drops of dilute acid to a test tube containing the substance
Connect the test tube to a test tube containing lime water
If carbonate ions are present the reaction with the acid will release co2 and turn the lime water cloudy

Question 4

What do sulfates contain

Answer 4

Sulfate ions SO4*2-

Question 5

How do you identify sulfate ions

Answer 5

Use a dropping pipette to add a couple drops of dilute hydrochloric acid followed by barium chloride solution to w test tube
A white precipitation will from

Question 6

Why do you add hydrochloric acid to test for sulfate

Answer 6

To get rid of any traces of carbonate ions before you do the test and not end up with a precipitate

Question 7

How do you test for halide ions

Answer 7

Add a couple drops of nitric acid and then couple drops of silver nitrate solution

Question 8

What will Choride, bromide and iodide make if present in solution

Answer 8

Chloride = white precipitate of silver chloride 
Bromide = cream precipitate of silver bromide 
Iodine = yellow precipitate of silver iodide

Question 9

What are cations

Answer 9

Positive ions so metals

Question 10

How do you test for cations

Answer 10

Flame tests and seeing there colour

Question 11

What colour will lithium go

Answer 11

Crimson

Question 12

What colour will sodium go

Answer 12

Yellow

Question 13

What colour will postassium go

Answer 13

Lilac

Question 14

What colour will calcium go

Answer 14

Orange red flame

Question 15

What colour will copper go

Answer 15

Green flame

Question 16

How do you carry out flame tests

Answer 16

Clean a wire nichrome or platinum wire loop by running with fine emery paper and hold it in the blue flame until it stays a blue flame
Dip the loop into a sample and hold it in the flame

Question 17

What will metals form when mixed with sodium hydroxide and why is this

Answer 17

Many Metal hydroxide are insoluble and will form a coloured precipitate

Question 18

What colour will the precipitate of calcium go

Answer 18

White

Question 19

What colour will the precipitate of copper go

Answer 19

Blue

Question 20

What colour will the precipitate of iron2 go

Answer 20

Green

Question 21

What colour will the precipitate of iron3 go

Answer 21

Brown

Question 22

What colour will the precipitate of aluminium go

Answer 22

White at first

But the redissolves to form a colourless solution

Question 23

What colour will the precipitate of magnesium go

Answer 23

White

Question 24

What happens during flame emission spectroscopy

Answer 24

A sample is placed in a flame
The ion heats up and their electrons become excited so they move to higher energy levels
When the electrons drop back to their original energy levels they release energy as light
This light passes through a spectroscope and this can produce a line spectrum of the ion

Question 25

What does the combination of wavelengths emitted by an ion depend on

Answer 25

Its charge and electron arrangement

Question 26

Why does each ion produce a different pattern of wavelengths and different like spectrums

Answer 26

Because no two ions have the same charge and same election arrangement

Question 27

What can the line spectra be used for

Answer 27

To identify ions in solution and calculate their concentrations

Question 28

What can flame emission spectroscopy be used for and what does this mean

Answer 28

Identify different ions in mixtures and this makes it more useful than flame tests

Question 29

What are the advantages of using machine

Answer 29

They are very sensitive
Very fast
Very accurate