C 12 Chemical analysis

Question 1

pure substance in chemistry def

Answer 1

made up of only one substance, element or compound

Question 2

wht are fixed points

Answer 2

melting+boiling points of elements/compounds

Question 3

characteristics of pure substances boiling points

Answer 3

specific temperatures

Question 4

mixture

Answer 4

different particles

Question 5

element

Answer 5

only 1 type of atom

Question 6

compound

Answer 6

different types of atoms, but all particles are the same

Question 7

formulation

Answer 7

mixture that has been desgigneted as useful product

Question 8

examples of formulations

Answer 8

medicines, alloys, fertilisers, food, fuels
(gold alloys for jewellerly)

Question 9

how is a formulation made

Answer 9

mixing componets in carefully measured quantitiies

Question 10

purpose of chromatography.

Answer 10

seperate mixtuers and give info that hel to identify substances

Question 11

how are different dyes separated by paper chromatograhy

Answer 11

solvent moves through paper
different dyes have different solubilities in solvent
and different attractions for the paper
and so are carried different distances

Question 12

experiment of chromatograhy

Answer 12

draw (pencil) start line on (chromatography) paper
* place spot of food colouring on start line
* use of suitable solvent
* place solvent in beaker / container
* place (chromatography) paper in beaker / container
* so (chromatography) paper is in solvent
* but solvent is below start line
* use a lid
* wait for solvent to travel up the (chromatography) paper (until
near top)
* dry the (chromatography) paper
Measurements
* measure distance between start line and centre of spot
* measure distance between start line and solvent front
* use of measurements to determine Rf value

Question 13

2 phases of chromatography and examples

Answer 13

stationary phase =paper
mobile phase= solvent

Question 14

what will a pure sbstance always produce

Answer 14

single spot

Question 15

Rf formula

Answer 15

distance moved by substance : distance moved by solvent

Question 16

test for H

Answer 16

burning splint held at end of test tube.
lighted splint ‘pop’

Question 17

test for O

Answer 17

glowing splint into test tube of gas.
splint relights

Question 18

test for CO2

Answer 18

limewater turn milky

Question 19

test for chlorine

Answer 19

damp litumus paper into gas.
paper is bleached + turns white

Question 20

flame tests
lithium
sodium
potassium
calcium
copper

Answer 20

crimson
yellow
lilac
orange-red
green

Question 21

reaction with metal hydroxides
al
Mg
Ca
Cu
Fe2
Fe3

Answer 21

precipate colour
white (dissolves in excess)
white
white
blue
green brown

Question 22

ionic equation for metal hydroxides

Answer 22

Al3+ + 3OH- <– A(OH)3 (s)
Fe2+ +2OH- <–Fe(OH)2 (s)

Question 23

carbonate test

Answer 23

dilute acid and bubble thrugh limewater
result in fizzing+ limewater milky

Question 24

carbonate test equation

Answer 24

-
CO2-(inalto)3 + 2H+ <– CO2 +H2O

Question 25

sulfate test

Answer 25

add dilute hydrochloric acid . and the barium chloride solution result white precipitate

Question 26

sulfate equation

Answer 26

Ba2- + SO2-(alto)4 <-- BaSO4

Question 27

test Halides Cl Br I

Answer 27

add dilute nitric acid, then silver nitrate solution white precipitate cream yellow

Question 28

equation for halides (x- is the halide)

Answer 28

Ag+ + x- <--Agx (s)

Question 29

flame emission spectroscopy

Answer 29

used to analyse metal ions in solutions

Question 30

flame emission spectroscopy process

Answer 30

sample is put into flame and the light given out is passed through a spectroscope. outout is a line spectrum that will tell us metal ions present and measure concnetrations