chem paper 2 - worst topics

Question 1

greenhouse gases and air pollution

3 examples of effects of global warming

Answer 1

polar ice caps melting
rise in sea levels
loss of habitats

Question 2

effects of sulphur (3)

Answer 2

sulfur dioxide produced
causes acid rain leads to buildings and trees being damaged

Question 3

danger of carbon monoxide

Answer 3

its toxic

Question 4

what is/ consequence of soot (2)

Answer 4

these are particulates that contribute to global dimming

Question 5

human activites that increase carbon d in the atmosphere (3)

Answer 5

more greenhouse gas emissions from factory farming
more burning fossil fuels
more high levels of deforestation

Question 6

cations

flame test colour for calcium, copper potassium, lithium, sodium ions

Answer 6

orange-red
green
lilac
crimson
yellow

Question 7

halides

what is the test for a chloride ion (3 steps)

Answer 7

add dilute nitric acid, followed by silver nitrate solution
white precipitate is formed

Question 8

halides

what is the test for an iodide ion (3 steps)

Answer 8

add dilute nitric acid, then silver nitrate solution
yellow precipitate is formed

Question 9

anions

what is the test for sulfate ions (3 steps)

Answer 9

add dilute HCL acid to remve any carbonate ions
then barium chloride solution
white precipitate is formed of barium sulphate

Question 10

quick test for all the gases

Answer 10

hydrogen - lit splint squeaky pop
chlorine - bleaches damp blue litmus paper red then white
carbon d - limewater turns cloudy
oxygen - glowing splint relights

Question 11

describe the overall test for halide ions

what is one of the chemical equations

Answer 11

add dilute nitric acid
followed by silver nitrate or AgNO3
if halides are present a precipitate is formed

Question 12

how to do the flame test for cations (5)

the outline of steps not specific test results

Answer 12

1. take a platinum wire loop and clean it by dipping it in dilute HCL acid, rinse it in distilled water
2. heat it over bunsen burner flame
3. dip wire loop into the compound you’re testing
4. hold wire loop in the clear blue part of bunsen flame (the hottest part)
5. see the colour change of the flame as the compound burns

Question 13

cations

for sodium hydroxide tests (for metal ions) what colour is the magnesium precipitate

Answer 13

white

Question 14

cations

for sodium hydroxide tests (for metal ions) what colour is the aluminium precipitate

Answer 14

white at first then redissolves in excess sodium hydroxide to form a colourless solution

Question 15

cations

for sodium hydroxide tests (for metal ions) what colour is the copper precipitate

Answer 15

blue

Question 16

cations

for sodium hydroxide tests (for metal ions) what colour is the Fe 3+ (iron 3+) precipitate

Answer 16

brown

Question 17

cations

for sodium hydroxide tests (for metal ions) what colour is the calcium precipitate

Answer 17

white

Question 18

cations

for sodium hydroxide tests (for metal ions) what colour is the Fe 2+ (iron 2+) precipitate

Answer 18

green

Question 19

when testing halides what colours do chloride, bromide and iodide precipitates go

Answer 19

white, cream, yellow

Question 20

how to test for carbonate ions (4)
- when the substance is in a test tube

Answer 20

1. react substance with drops of dilute HCL acid from a pipette
2. if substance has carbonate ions
3. carbon dioxide gas is produced as bubbles out of solution
4. limewater goes cloudy proving original substance had carbonate ions