Chemical Anaylsis

Question 1

whats something thats pure?

Answer 1

only one compound or element.

Question 2

how can you test the purity of a substance?

Answer 2

measure its mp or bp and compare it to mp and bp of pure substance.

Question 3

what do impurities increase?

Answer 3

the boiling point.

Question 4

how are formulations important in the pharmaceutical industy?

Answer 4

by altering formulation of a pill chemists can make sure it delivers to right part of body at right concentration.

Question 5

where are formulations found in everyday life?

Answer 5

cleaning products, fuels, cosmetics, fertilisers, metal alloys, food and drink.

Question 6

whats chromatography used for?

Answer 6

analytical method used to separate substances in a mixture.

Question 7

whats the mobile phase?

Answer 7

molecules can move, liquid or gas.

Question 8

whats the stationary phase?

Answer 8

molecules cant move, solid or really thick liquid

Question 9

what happens to the chemicals that spent more time in the mobile phase?

Answer 9

they will move further through the stationary phase.

Question 10

in paper chromatography what is the stationary phase and what is the mobile phase?

Answer 10

stationary phase- chromatography paper
mobile phase- solvent e.g ethanol or water

Question 11

whats the Rf value?

Answer 11

distance travelled by substance/ distance travelled by solvent

Question 12

whats the result of a chlorine test?

Answer 12

bleached litmas paper

Question 13

oxygen present?

Answer 13

relight a glowing splint

Question 14

carbon dioxide present?

Answer 14

turns limewater cloudy.

Question 15

hydrogen present?

Answer 15

squeaky pop

Question 16

how can you test for carbonates?

Answer 16

Put sample in test tube.
use pipette to add dilute acid
connect with test tube of limewater
if carbonate is present carbon dioxide will be released turning limewater cloudy.

Question 17

what precipitate is formed from barium sulfate?

Answer 17

a white precipitate.

Question 18

how do you test for halides?

Answer 18

add dilute acid and silver nitrate solution

Question 19

what precipitate is formed from silver chloride?

Answer 19

white

Question 20

what precipitate is formed from silver bromide?

Answer 20

cream

Question 21

what precipitate is formed from silver iodide.

Answer 21

yelllow

Question 22

what colour do lithium ions burn with?

Answer 22

crimson

Question 23

what colour do sodium ions burn with?

Answer 23

yellow

Question 24

what colour do potassium ions burn with?

Answer 24

lilac

Question 25

what colour do calcium ions burn with?

Answer 25

orange-red flame

Question 26

what colour do copper ions burn with?

Answer 26

green flame

Question 27

how do you clean the wire loop for the flame test?

Answer 27

dip loop in dilute HCI then hold it in blue flame until it burns with no colour.

Question 28

what precipitate does calcium form?

Answer 28

white

Question 29

what precipitate does copper (II) form?

Answer 29

blue

Question 30

what precipitate does Iron (II) form?

Answer 30

green

Question 31

what precipitate does Iron (III) form?

Answer 31

Brown

Question 32

what precipitate does aluminium form?

Answer 32

white and first, redissolves in excess to form colourless solution

Question 33

what precipitate does Magnesium form?

Answer 33

white

Question 34

what happens during flame emission spectroscopy?

Answer 34

sample placed in flame
ions heat up and electrons become excited
electrons drop back to originals energy levels
energy is then transfered as light
light passed spectroscope, detect different wavelengths of light to produce line spectrum

Question 35

what does the intensity of the light spectrum indicate?

Answer 35

concentration of that ion in solution

Question 36

what are advantages of instrumental analysis?

Answer 36

very sensitive, very fast, very accurate