Chapter 4 - Acids and Redox (MODULE 2) Flashcards

1
Q

what is released when acids dissolve in water

A

H+ ions

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2
Q

What is a strong acid

A

one which releases all its H+ ions into solution and completely dissociates in aqueous solution

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3
Q

What is a weak acid

A

one which doesn’t release all its H+ ions into solution and partially dissociates in aqueous solution

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4
Q

WHat are some examples of strong acids

A

HCl. H2SO4, HNO3

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5
Q

What are some examples of weak acids

A

ethanoic acid, most organic acids

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6
Q

What sign is used to indicate the forward reaction is incomplete

A

equilibrium arrow

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7
Q

What are some general examples of bases

A

metal oxides, metal hydroxides, metal carbonates and ammonia

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8
Q

what is the reaction between an acid and base called
- what is always produced

A

neutralisation
- a salt

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9
Q

What is an alkali

A

a base that dissolves in water releasing OH- ions into solution

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10
Q

How is a salt formed in neutralisation

A

H+ ion in acid is replaced by metal or ammonium ions from base

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11
Q

What are the general products for acid + metal

A

salt + hydrogen

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12
Q

What are the general products for acid + metal oxide

A

salt + water

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13
Q

What are the general products for acid + metal hydroxide

A

salt + water

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14
Q

What are the general products for acid + metal carbonate

A

salt + water + carbon dioxide

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15
Q

What is a titration used for

A

accurately measuring the volume of one solution that reacts exactly with another solution

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16
Q

What are the 3 main uses of titrations

A
  • finding the concentration of a solution
  • identification of unknown chemicals
  • finding the purity of a substance
17
Q

What is a standard solution

A

a solution of known concentration

18
Q

What are standard solutions made in

A

volumetric flasks

19
Q

what are the typical tolerances of:

  • 100cm^3
  • 250cm^3
    volumetric flasks
A
  • ±0.20cm^3
  • ±0.30cm^3
20
Q

in an acid - base titration, what measuring apparatus is used

A

pipette and burette

21
Q

what are the typical tolerances of

  • 10cm^3 pipette
  • 25cm^3 pipette
  • 50cm^3 burette
A
  • ± 0.04cm^3
  • ± 0.06cm^3
  • ± 0.10cm^3
22
Q

How are burettes always read

A
  • from the bottom of the meniscus
  • to the nearest half-division (0.05cm^3)
  • always 2 d.p.
23
Q

How do you calculate the mean titre

A

work out the mean of 2 concordant titres

24
Q

what are concordant titres

A

titres within 0.10cm^3 of each other

25
What is the oxidation number of elements
0
26
What is the usual oxidation number for - O - H - F - group 1 - Group 2 - Halides
: -2 : +1 : -1 : +1 : +2 : -1
27
What are the oxidation numbers for - H in metal Hydrides - O in peroxides - O bonded to F
- -1 - -1 - +2
28
What is the sum of oxidation numbers in a compound equal to
the overall charge
29
what does the roman numeral in the names of compounds show
the oxidation number of the element without a sign
30
what is the charge of N in - NO2 (-) - NO3 (-)
- nitrate (III) (+3) - nitrate (V) (+5)
31
Given that roman numerals are omitted for more common ions, what is the formula of what is called - nitrate - sulfate
- NO3 (-) - SO4 (2-)
32
What is oxidation in terms of electrons
the loss of electrons
33
What is reduction in terms of electrons
the gain of electrons
34
What is oxidation in terms of oxidation number
an increase in oxidation number
35
What is reduction in terms of oxidation number
a decrease in oxidation number
36
what is a redox reaction
one where both reduction and oxidation occurs