Danho
ZIMSEC A Level · N2004

Chemistry Paper 2 November 2004

Questions
27
Total marks
39
Time allowed
75 min

Sit this paper online

Questions
27
Pass mark
17
Sit this paper

Answer every question in the printed order, get marked at the end, then see the answers.

The questions

Question 101

[1 marks]acid-base equilibria and buffers
A buffer solution is one which
  1. Aresists a change in pH when a little acid or alkali is added
  2. Bcontains equal volumes of an acid and an alkali
  3. Chas a pH of exactly 7
  4. Dneutralises any acid added to it

Question 102

[1 marks]acid-base equilibria and buffers
20.00 cm320.00\ cm^3 of aqueous ammonia required 20.00 cm320.00\ cm^3 of 0.1 mol dm−30.1\ mol\,dm^{-3} hydrochloric acid for complete neutralisation. The concentration of the ammonia, in mol dm−3mol\,dm^{-3}, is
  1. A0.05
  2. B0.10
  3. C0.20
  4. D1.00

Question 103

[1 marks]acid-base equilibria and buffers
Aqueous ammonia is titrated with hydrochloric acid. Given that Ka(NH4+)=5.6×10−10 mol dm−3K_a(NH_4^+) = 5.6 \times 10^{-10}\ mol\,dm^{-3}, the pH of the mixture halfway to the end point is
  1. A4.75
  2. B9.25
  3. C10.20
  4. D11.20

Question 104

[1 marks]acid-base equilibria and buffers
pH is defined by the expression pH =

Answer this when you sit the paper.

Question 105

[1 marks]acid-base equilibria and buffers
Write a balanced equation for the neutralisation of aqueous ammonia by hydrochloric acid.

Answer this when you sit the paper.

Question 106

[2 marks]acid-base equilibria and buffers
The pH halfway to the end point (9.25) is lower than the initial pH of the ammonia solution (11.20) because
  1. Aadding hydrochloric acid always raises the pH of any solution it is added to
  2. Bthe ammonia solution becomes more concentrated as acid is added, lowering its pH
  3. Cat the halfway point, the NH4+ formed acts as a weak acid, partially neutralising the excess OH- and lowering the pH
  4. Dwater is produced in the reaction, which is itself acidic and lowers the pH

Question 107

[2 marks]acid-base equilibria and buffers
The initial ammonia solution has pH 11.20. Its pOH (given pKw = 14 at 25 degrees C) is

Answer this when you sit the paper.

Question 201

[1 marks]chemical equilibrium
The equation for the reaction between iodine and sodium thiosulphate is
  1. AI2+S2O32−→2I−+S4O62−I_2 + S_2O_3^{2-} \rightarrow 2I^- + S_4O_6^{2-}
  2. BI2+2S2O32−→2I−+2SO42−I_2 + 2S_2O_3^{2-} \rightarrow 2I^- + 2SO_4^{2-}
  3. C2I−+S4O62−→I2+2S2O32−2I^- + S_4O_6^{2-} \rightarrow I_2 + 2S_2O_3^{2-}
  4. DI2+2S2O32−→2I−+S4O62−I_2 + 2S_2O_3^{2-} \rightarrow 2I^- + S_4O_6^{2-}

Question 202

[1 marks]chemical equilibrium
A 50 cm350\ cm^3 portion of an equilibrium mixture required 30.0 cm330.0\ cm^3 of 0.1 mol dm−30.1\ mol\,dm^{-3} sodium thiosulphate. The concentration of iodine in the mixture, in mol dm−3mol\,dm^{-3}, is
  1. A0.015
  2. B0.030
  3. C0.059
  4. D0.060

Question 203

[1 marks]chemical equilibrium
At equilibrium for I2(aq)+I−(aq)⇌I3−(aq)I_2(aq) + I^-(aq) \rightleftharpoons I_3^-(aq) the concentrations are [I2]=0.030[I_2] = 0.030, [I−]=0.129[I^-] = 0.129 and [I3−]=0.029 mol dm−3[I_3^-] = 0.029\ mol\,dm^{-3}. KcK_c, in dm3 mol−1dm^3\,mol^{-1}, is
  1. A0.13
  2. B1.5
  3. C7.5
  4. D15.0

Question 204

[2 marks]chemical equilibrium
Calculate the equilibrium concentration of I−I^- ions, given the initial iodide concentration was 0.158 mol dm-3 and 0.029 mol dm-3 of I2I_2 reacted.

Answer this when you sit the paper.

Question 205

[1 marks]chemical equilibrium
Calculate the equilibrium concentration of I3−I_3^- ions, given that 0.029 mol dm-3 of I2I_2 reacted to form I3−I_3^-.

Answer this when you sit the paper.

Question 206

[2 marks]chemical equilibrium
For the equilibrium I2(aq)+I−(aq)⇌I3−(aq)I_2(aq) + I^-(aq) \rightleftharpoons I_3^-(aq), the correct expression for KcK_c is
  1. AKc=[I3−][I2][I−]K_c = \dfrac{[I_3^-]}{[I_2][I^-]}
  2. BKc=[I2][I−][I3−]K_c = \dfrac{[I_2][I^-]}{[I_3^-]}
  3. CKc=[I2][I−][I3−]K_c = [I_2][I^-][I_3^-]
  4. DKc=[I3−][I2]+[I−]K_c = \dfrac{[I_3^-]}{[I_2]+[I^-]}

Question 301

[1 marks]period 3 oxides and inorganic reactions
Aluminium oxide dissolves both in aqueous sodium hydroxide and in dilute hydrochloric acid. Aluminium oxide is therefore
  1. Aneutral
  2. Bamphoteric
  3. Cacidic
  4. Dbasic

Question 302

[1 marks]period 3 oxides and inorganic reactions
The ionic equation for the reaction of sulphur dioxide with aqueous sodium hydroxide is
  1. ASO2+OH−→HSO4−SO_2 + OH^- \rightarrow HSO_4^-
  2. BSO2+2OH−→SO42−+H2SO_2 + 2OH^- \rightarrow SO_4^{2-} + H_2
  3. CSO2+H2O→SO32−+2H+SO_2 + H_2O \rightarrow SO_3^{2-} + 2H^+
  4. DSO2+2OH−→SO32−+H2OSO_2 + 2OH^- \rightarrow SO_3^{2-} + H_2O

Question 303

[1 marks]period 3 oxides and inorganic reactions
On heating, a white stone gave a colourless acidic gas and a white residue which formed calcium hydroxide with water. The stone contains
  1. Acalcium hydrogencarbonate
  2. Bcalcium nitrate
  3. Ccalcium sulphate
  4. Dcalcium carbonate

Question 304

[2 marks]period 3 oxides and inorganic reactions
State the formulae of the oxides formed by sodium and by silicon, the first and fourth elements of Period 3.

Answer this when you sit the paper.

Question 305

[1 marks]period 3 oxides and inorganic reactions
The reaction of sulphur dioxide with dilute hydrochloric acid is
  1. Ano reaction, since both are acidic
  2. Ba vigorous reaction giving sulphuric acid
  3. Ca redox reaction giving sulphur and water
  4. Da precipitation reaction giving a white solid

Question 306

[1 marks]period 3 oxides and inorganic reactions
The white residue B, which reacts with water to give calcium hydroxide, is

Answer this when you sit the paper.

Question 307

[2 marks]period 3 oxides and inorganic reactions
Write the ionic equation for the reaction of aluminium oxide with aqueous sodium hydroxide.

Answer this when you sit the paper.

Question 401

[1 marks]organic chemistry - functional groups
Oestradiol contains both a phenolic −OH-OH group and an alcoholic −OH-OH group. The reagent which reacts with the phenolic group only is
  1. Asodium metal
  2. Baqueous sodium hydroxide
  3. Cacidified potassium dichromate(VI)
  4. Dethanoic acid and concentrated sulphuric acid

Question 402

[1 marks]organic chemistry - functional groups
The order of increasing acidity of ethanol, water and a phenol is
  1. Aphenol < ethanol < water
  2. Bethanol < water < phenol
  3. Cphenol < water < ethanol
  4. Dwater < ethanol < phenol

Question 403

[1 marks]organic chemistry - functional groups
Oestradiol is warmed with ethanoic acid in the presence of a little concentrated sulphuric acid. The type of reaction which occurs is
  1. Ahydrolysis
  2. Boxidation
  3. Cesterification
  4. Daddition

Question 404

[1 marks]organic chemistry - functional groups
The number of chiral centres in the oestradiol molecule is

Answer this when you sit the paper.

Question 405

[2 marks]organic chemistry - functional groups
When oestradiol reacts with excess sodium metal, the observation and reaction type are
  1. Aformation of a white precipitate, as sodium displaces the phenol as an insoluble salt
  2. Bno observable reaction, since sodium is unreactive with alcohols and phenols
  3. Ceffervescence of hydrogen gas, as sodium reacts with both the phenolic and the alcoholic -OH groups
  4. Da colour change from orange to green, as sodium reduces the aromatic ring

Question 406

[2 marks]organic chemistry - functional groups
When oestradiol is treated with aqueous bromine in the dark, the observation and reaction type are
  1. Athe bromine water is decolourised and a white precipitate forms, by electrophilic substitution onto the activated aromatic ring
  2. Bthe solution turns deep blue, indicating complex formation with the phenol
  3. Cno reaction, since the ring has no double bonds available for addition
  4. Da brown gas is evolved, as bromine oxidises the alcohol group to a ketone

Question 407

[2 marks]organic chemistry - functional groups
The phenolic -OH of oestradiol is more acidic than the -OH of water or ethanol because
  1. Aoestradiol has a much larger molecular mass than either water or ethanol
  2. Bthe phenoxide ion formed on losing H+ is stabilised by delocalisation of its negative charge into the aromatic ring
  3. Cphenols always dissociate completely in water, unlike water or ethanol
  4. Dthe aromatic ring pushes electron density onto the -OH oxygen, weakening the O-H bond

More sittings of this paper

The answers, and why they are the answers

Sit the paper here to see which ones you got right. Danho explains every question, keeps your score, and works without a connection.

Get it on Google PlayDownload on the App Store