ID and gases Flashcards

1
Q

ammonia test

A

damp UI / red litmus paper
goes blue

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2
Q

CO2 gas test

A

limewater
goes cloudy

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3
Q

Cl2 gas test

A

damp UI/blue litmus paper
goes red then beaches

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4
Q

CO2 test - equation

A

Ca(OH)2 (aq) + CO2(g) > CaCO3(s) + H2O(l)

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5
Q

Cl2 test equations

A

Cl2(g) + H2O(l) > HCl + HOCl

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6
Q

H2 gas test

A

lit splint
squeaky pop

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7
Q

H2 gas equation

A

2H2 + O2 > 2H2O

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8
Q

O2 gas test

A

glowing splint
relights

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9
Q

water vapour test

A

anyhdrous copper sulphate (white)
goes blue

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10
Q

carbonate ions test

A

+acid - effervescence
bubble through limewater - clear>cloudy (proves CO2 made)

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11
Q

carbonate ions - equation

A

2H,+(aq) + CO3,2-(aq) > H2O(l) + CO2(g)

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12
Q

sulphate ions test

A

add acid eg HCl (to remove carbonate ions and wont interfere with BaCl2)
add anything with barium ions in eg BaCl2 - white ppt.

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13
Q

sulphate ions test equation

A

SO4,2-(aq) + Ba,2+(aq) > BaSO4(s)

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14
Q

halide ions test

A

add HNO3 (remove carbonate ions, wont interfere as has nitrate ions in)
add AgNO3
result
- Cl2 - white
- Br2 - creme
- I2 - yellow

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15
Q

halide ions test equation eg Br2

A

Br,-(aq) + Ag,+(aq) > AgBr(s)

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16
Q

flame test method

A
  • dip nichrome wire into HCl(aq) + heat in roaring flame to clean wire
  • dip wire back into HCl and into the test substance so it sticks to wire
  • put wire in the roaring flame and observe the colour
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17
Q

sodium flame colour

A

orange

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18
Q

lithium flame colour

A

crimson

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19
Q

potassium flame colour

A

lilac

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20
Q

calcium flame colour

A

brick red

21
Q

copper flame colour

A

blue-green

22
Q

magnesium flame colour

A

none

23
Q

copper ion test

A

add NaOH
goes blue

24
Q

iron(II) ion test

A

add NaOH
goes green

25
Q

iron(III) ion test

A

add NaOH
goes red-brown

26
Q

why does iron(II) hydroxide ppt. darken on standing

A

oxidises in air

27
Q

ammonium ion test

A
  • add sodium hydroxide
  • heat gently
  • test gas with damp UI paper(goes blue) as ammonia is evolved
28
Q

ammonium ion test equation

A

NH4,+(aq) + OH,-(aq) > NH3(g) + H2O(l)

29
Q

pure water test

A

exact boiling point 100C

30
Q

composition of air

A

N2 - 78%
O2 - 21%
other gases - Ar(0.9%) CO2(0.035%) water vapour/noble gases(0.065%)

31
Q

finding % of oxygen in air

A
  • copper + oxygen react
  • iron fillings rust
  • add phosphorous
32
Q

finding % of oxygen in air - copper and oxygen react

A
  • 100ml gas passed over excess fine copper pieces (large SA to react + Cu isn’t limiting)
  • heated
  • as O2 reacts with Cu amount reduces
  • when no more change in volume stop heat
  • left to cool (gas un-expands back to normal)
  • measure volume at end and calculate vol of O2 present and %in air
33
Q

finding % of oxygen in air - iron filing rust

A
  • iron fillings held onto inside of boiling tube with vaseline
  • put upside down in a water bath
  • water level rises as vol of gas decreases as it reacts with iron so water takes gases place
  • water level rises to constant level once all O2 has reacted
    (use measuring cylinder to measure volume of air at start/end and find % of O2 in air)
34
Q

finding % of oxygen in air - phosphorus

A

P4 + 5O2 > P4O10
similar to iron as it burns and reacts water level rises
phosphorus goes out when all O2 has reacted
use % change of volume = % of O2 reacted (%of O2 in air)

35
Q

CO2 uses

A
  • make fizzy drinks - slightly soluble in H2O to form carbonic acid
  • fire extinguisher - denser than air - smothers O2
  • dry ice
  • packaging to stop oxidation - inert
36
Q

make CO2

A

react carbonates + acid
- CaCO3(s) + 2HCl(aq) > CaCl2(aq) + H2O(l) + CO2(g)
- speed up - heat, mix, smaller pieces of reactant, higher concentration of HCl

thermal decomposition of metal carbonate
- heat copper carbonate - green>black

37
Q

CO2 as a greenhouse gas

A

can absorb infrared radiation radiated from Earth
increased CO2 traps more heat (leading to global warming)

38
Q

thermal decomposition to copper carbonate

A

CuCO3(s)>(heat)> CuO(s) +CO2(g)
- green > black

39
Q

CO2 - pollutant

A

formed
- respiration
- combustion of fossil fuels
- organic decomposition

greenhouse gas
- more CO2 leads to global warming

solution
- reduce CO2 in sky - plant trees - conserve forests(remove CO2 by photosynthesis) - capture CO2 from plants/factories

40
Q

CO - pollutant

A

formed
- incomplete combustion of fossil fuels

TOXIC
- combines with haemoglobin so blood carries less O2

solutions
- clean heating systems (prevent soot build up) -ensure complete combustion
- CO detector

41
Q

Sulphur dioxide - pollutant

A

formed
- burning fossil fuels (coal)

acid rain
- kills plants/ acidifies lakes
- weathers limestone/ erodes building

solutions
- wash coal to remove sulphur before burning
- use less sulphur coals
- scrubbers remove SO2

42
Q

nitrogen oxides - pollutant

A

formed
- combustion - when fossil fuels burn
- oxidations of N2 in engines

  • lung disease (asthma)
  • acid rain - harm vegitation
  • photochemical smog

solutions
- use less nitrogen fertiliser
- use low nitrogen burners
- catalytic converters

43
Q

burning metals

A

form basic oxides
turn UI blue

44
Q

burning non-metals

A

form acidic oxides

45
Q

1dm^3 to cm^3

A

1000cm^3

46
Q

molar gas volume at room temp and atmospheric pressure

A

24 dm^3/mol

47
Q

moles (gases)

A

n = volume (dm^3)/ 24

48
Q

moles solids

A

n = mass(g) / Mr

49
Q

moles (solutions)

A

n = volume (dm^3) X concentration (moldm^-3)