quantitative analysis Flashcards

1
Q

when is a gas evolved in a reaction?

A

effervescence, colour/odour of gas is detected, when a solid substance is heated

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2
Q

what is the effect of oxygen on moist litmus paper?

A

no effect, oxygen gas is neutral

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3
Q

what are colourless and odourless gases that can be tested for?

A

oxygen, hydrogen, carbon dioxide

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4
Q

what is the effect of hydrogen gas on moist litmus paper?

A

no effect, hydrogen gas is neutral

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5
Q

what is the effect of carbon dioxide on moist litmus paper?

A

gas will turn moist blue litmus paper red, gas is acidic

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6
Q

what is the test for oxygen?

A

by inserting a glowing splint into the test tube, if the glowing splint is relit, oxygen is present

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7
Q

what is the test for hydrogen?

A

if a lighted splint is extinguished with a ‘pop’ sound, hydrogen is present

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8
Q

why does oxygen gas rekindle a lighted splint?

A

oxygen gas supports combustion

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9
Q

what is the test for carbon dioxide?

A

if bubbled gas in limewater forms a white precipitate, carbon dioxide is present

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10
Q

describe ammonia gas

A

colourless gas with a pungent smell

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11
Q

what is the test for ammonia gas?

A

if moist red litmus paper turns blue, ammonia gas is present (alkaline)

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12
Q

describe chlorine gas

A

greenish-yellow gas with a pungent smell

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13
Q

what is the reaction of chlorine gas with moist litmus paper and what is the conclusion?

A

will turn moist blue litmus paper to red and then bleached, gas is acidic

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14
Q

describe sulfur dioxide

A

colourless gas witha pungent smell

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15
Q

how does sulfur dioxide react with moist litmus paper?

A

turns moist blue litmus paper red (acidic)

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16
Q

how does Ca2+ react with aqueous sodium hydroxide?

A

white preciptate is formed which is insoluble in excess NaOH

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17
Q

what is the ionic equation of calcium + aqueous sodium hydroxide?

A

Ca2+ (aq) + 2OH- (aq) -> Ca(OH)2 (s)

18
Q

how does Al3+ react with aqueous sodium hydroxide?

A

white precipitate is formed which dissolves in excess NaOH to give a colourless solutioin

19
Q

how does Pb2+ react in aqueous sodium hydroxide

A

white precipitate is formed which dissolves in excess NaOH to give colourless solution

20
Q

how does Fe2+ react in aqueous sodium hydroxide?

A

dirty green precipitate is formed which is insoluble in excess NaOH which turns reddish brown on standing

21
Q

how does Fe3+ react in aqueous sodium hydroxide?

A

reddish-brown precipitate is fo0rmed which is insoluble in excess NaOH

22
Q

how does Cu2+ react in aqueous sodium hydroxide?

A

light blue precipitate is formed which is insoluble in excess NaOH

23
Q

how does NH4+ react in aqueous sodium hydroxide?

A

no precipitate is formed, on heating a gas evolved turns moist red litmus paper rblue

24
Q

how does Ca2+ react with aqueous ammonia?

A

no precipitate is observed

25
Q

how does Al3+ react with aqueous ammonia?

A

white precipitate is formed which is insoluble in excess aqueous ammonia

26
Q

how does Pb2+ react with aqueous ammonia?

A

white precipitate is formed which in insoluble in excess aqueous ammonia

27
Q

how does Zn2+ react with aqueous ammonia?

A

white precipitate is formed which dissolves in excess aqueous ammonia to give a colourless solution

28
Q

how does Fe2+ react with aqueous ammonia?

A

dirty green precipiate is formed which is insoluble in excess aqueous ammonia and turns reddish brown on standing

29
Q

how does Fe3+ react with aqueous ammonia?

A

reddish-brown precipiate is formed which is insoluble in excess aqueous ammonia

30
Q

how does Cu2+ react with aqueous ammonia
?

A

light blue precipitate is formed and is soluble in excess aqueous ammonia

31
Q

how do you differentiate Al3+ and Pb2+ ions?

A

add aqueous Hcl/NaCl, if Pb2+: white precipitate, Al3+: white precipitate :

32
Q

how do you test for CO3^2-?

A

addin dilute HCl and pass the gas given off into limewater

33
Q

what is the observation for carbonate test?

A

effervescence is observed and gas given off forms a white precipiate with limewater and carbon dioxide gas is given off

34
Q

how do you test for NO3^-?

A

add dilute sodium hydroxide followed by aluminium and warm gently

35
Q

what is the observation for nitrate ion?

A

a colourless gas with a pungent smell is evolved on warning, it turns moist red litmus paper blue and ammonia gas is given off

36
Q

how do you test for Cl-?

A

add dilute nitric acid followed by aqueous silver nitrate/add dilute nitric acid follows by aqueous lead (ii) nitrate

37
Q

what is the observation for chloride ion?

A

white precipitate is observed

38
Q

how do you test for I- ion?

A

add dilute nbitric acid followed by aqueous silver nitrate/add dilute nitric acid follows by aqueous lead (ii) nitrate

39
Q

what is the observation for iodide ion?

A

yellow precipitate is observed

40
Q

how do you test for So4^2-?

A

add dilute nitric acid/follows by aqueous barium nitrate/add dilute hydrochloric acid followed by aqueous barium chloride