Mock 2009 Flashcards Preview

Chemistry exam questions > Mock 2009 > Flashcards

Flashcards in Mock 2009 Deck (86)
Loading flashcards...
1
Q

In an experiment to determine the mass of iron in an iron tablet, describe in detail the procedure for making up the 250 cm³ solution from the tablets.

A

z

2
Q

In an experiment to determine the mass of iron in an iron tablet, explain the colour change observed as the first few drops of the potassium manganate (VII), KMnO4 solution was added to the flask.

A

x

3
Q

In an experiment to determine the mass of iron in an iron tablet, how was the end-point detected?

A

xx

4
Q

In an experiment to determine the mass of iron in an iron tablet, why was dilute sulfuric acid added before the titrations were commenced?

A

x

5
Q

In an experiment to determine the mass of iron in an iron tablet, explain why nitric acid could not be used to provide acidic conditions for this reaction.

A

x

6
Q

The titration reaction is described by the equation:
MnO₄- + 5Fe₂+ + 8H+ → Mn₂+ + 5Fe₃+ + 4H₂O
Calculate: (i) The concentration of the iron (II) solution in moles per litre.

A

x

7
Q

The titration reaction is described by the equation:
MnO₄- + 5Fe₂+ + 8H+ → Mn₂+ + 5Fe₃+ + 4H₂O
Calculate: (ii) The mass of iron (II) in one tablet.

A

x

8
Q

The titration reaction is described by the equation:
MnO₄- + 5Fe₂+ + 8H+ → Mn₂+ + 5Fe₃+ + 4H₂O
Calculate: (iii) The percentage by mass of iron (II) in each tablet.

A

x

9
Q

A group of students prepared ethanal (CH₃CHO) by slowly adding an aqueous solution of ethanol (C₂H₅OH) and sodium dichromate (VI) (Na₂Cr₂O₇.2H₂O) to a hot aqueous solution of sulfuric acid (H₂SO₄). State and explain two features of the preparation that are necessary to ensure the yield of ethanal is maximized.

A

x

10
Q

A group of students prepared ethanal (CH₃CHO) by slowly adding an aqueous solution of ethanol (C₂H₅OH) and sodium dichromate (VI) (Na₂Cr₂O₇.2H₂O) to a hot aqueous solution of sulfuric acid (H₂SO₄).The ethanol/oxidizing agent mixture was added slowly to the hot acid, explain why this was necessary.

A

x

11
Q

A group of students prepared ethanal (CH₃CHO) by slowly adding an aqueous solution of ethanol (C₂H₅OH) and sodium dichromate (VI) (Na₂Cr₂O₇.2H₂O) to a hot aqueous solution of sulfuric acid (H₂SO₄). State and explain the colour change which is observed during the addition of the ethanol and sodium dichromate (VI) solution to the hot acid.

A

x

12
Q

Describe how you would carry out the ‘Silver Mirror’ test on a sample of ethanal.

A

x

13
Q

If the students used 4.47g of sodium dichromate (VI) (Na₂Cr₂O₇.2H₂O) and they collected 2.0cm³ of ethanal (density 0.78g/cm³), in this experiment what was their % yield. [Relative atomic masses: H = 1, C = 12, O = 16, Na = 23, Cr = 52,]

A

x

14
Q

question 3 not in here

A

x

15
Q

Describe how a flame test may be carried out to determine the presence of a metal in a salt.

A

x

16
Q

In such a flame test, state the flame colour which indicates the presence of (i) the copper cation and (ii) the potassium cation in solution?

A

x

17
Q

Name the series of coloured lines in the line emission spectrum of hydrogen corresponding to transitions of electrons from higher energy levels to the second
(n = 2) energy level.

A

x

18
Q

Define electronegativity.

A

x

19
Q

What is the percentage by mass of chromium in sodium dichromate (VI) Na₂Cr₂O₇?

A

x

20
Q

Name the two reference hydrocarbons used to measure the octane number of a fuel.

A

x

21
Q

What are the two possible shapes of molecules of general formula AB₃?

A

x

22
Q

Name the product formed when bromine Br₂ is added to ethene C₂H₄.

A

x

23
Q

What is the oxidation number of manganese in (i) MnO and (ii) KMnO₄?

A

x

24
Q

Explain how particle size can affect the rate of a chemical reaction.

A

x

25
Q

What is the underlying principle of ultraviolet absorption spectroscopy (UV)?

A

x

26
Q

Give the systematic name of the two isomers of C₃H₆O.

A

xx

27
Q

State two ways in which nitrogen fixation occurs in nature.

A

x

28
Q

Name the material used in the anode to extract sodium from its ore in a Downs Cell.

A

x

29
Q

Define first ionization energy.

A

x

30
Q

Account for the trend in first ionisation energies of the elements going down Group II of periodic table, i.e. the alkaline-earth metals.

A

x

31
Q

Define (i) energy level and (ii) atomic orbital.

A

x

32
Q

Write the electron configuration (s, p, etc.) of a chromium atom in its ground state.

A

x

33
Q

Use the electronegativity values provided in the log tables to predict the bond type in the following compounds. (i) NaBr, (ii) H₂O, (iii) PH₃

A

x

34
Q

State the shape of the H₂O molecule and explain it’s high boiling point.

A

x

35
Q

Name two components of LPG. To what homologous series do these components belong?

A

x

36
Q

Outline how the fractioning process is carried out in an oil refinery.

A

x

37
Q

Name the fraction of crude oil which is used to form petrol.

A

x

38
Q

Define the terms (i) heat of reaction and (ii) heat of formation.

A

x

39
Q

Given the heats of formation of methane and water are –74kJ/mol and –285kJ/ mol respectively and the heat of combustion of methane is –890kJ/mol, calculate the heat of combustion of carbon.

A

x

40
Q

Define the rate of a chemical reaction.

A

x

41
Q

Na₂S₂O₃ + 2HCl → 2NaCl + H₂O + SO₂ + S

Describe how this reaction can be used to demonstrate the effect of: Temperarture

A

x

42
Q

Na₂S₂O₃ + 2HCl → 2NaCl + H₂O + SO₂ + S

Describe how this reaction can be used to demonstrate the effect of: Concentration on the rate of a chemical reaction.

A

x

43
Q

What is a catalyst?

A

x

44
Q

State the difference between a homogeneous and a heterogeneous catalyst.

A

x

45
Q

N₂ + 3H₂ |(Fe)⇋| 2NH₃

State the theory that best describes how iron catalyses the gaseous reaction between nitrogen and hydrogen above.

A

x

46
Q

Describe in terms of the stated theory how the catalyst works.

A

x

47
Q

Name the compound: C₂H₅OH

A

x

48
Q

Name the compound: CH₃CHO

A

x

49
Q

Name the compound: CH₃COOH

A

x

50
Q

Name the compound: CH₃COOCH₃

A

xx

51
Q

Name the homologous series to which (i) CH₃CHO belongs and (ii) CH₃COOCH₃ belongs?

A

x

52
Q

C₂H₅OH, CH₃CHO, CH₃COOH, CH₃COOCH₃

Identify the compound which contains only tetrahedral carbons.

A

x

53
Q

Classify the conversions X, Y and Z as an addition, substitution or oxidation reaction.
X Y Z
C₂H₅OH → CH₃CHO → CH₃COOH → CH₃COOCH₃

A

x

54
Q

Name the reagent and the catalyst used in the conversion of CH₃CHO → CH₃COOH

A

x

55
Q

Draw the structure of and name the carboxylic acid isomer of compound CH₃COOCH₃.

A

xx

56
Q

The compound CH₃COOH reacts with the base sodium carbonate Na₂CO₃. Write the balanced equation for this reaction.

A

x

57
Q

Distinguish between the terms permanent hardness and temporary hardness under the following headings: (i) Compound which causes each. (ii) Methods of their removal.

A

x

58
Q

Name a substance used to determine by titration the total hardness present in a water sample.

A

xx

59
Q

Name the indicator used in the titration to determine the total hardness present in a water sample and state the colour change observed at the end point.

A

x

60
Q

Identify (i) a conjugate pair and (ii) the species acting as acids in the following system.
SO₃²- + HCN → HSO₃- + CN-

A

x

61
Q

SO₃²- + HCN → HSO₃- + CN-

Calculate the pH of a 0.001M solution of sodium hydroxide (NaOH).

A

x

62
Q

SO₃²- + HCN → HSO₃- + CN-

Calculate the pH of a 0.001M solution of ammonia (NH₃) given that the Kb value of ammonia is 1.8 x 10-₅.

A

x

63
Q

In 1910 Rutherford (pictured right) and his co-workers carried out an experiment in which thin sheets of gold foil were bombarded with alpha particles. What is an alpha particle and give an example of an alpha emitter?

A

x

64
Q

Three observations were made during the experiment that helped Rutherford deduce that the atom has a nucleus. State these three observations and what Rutherford’s explanation for each was.

A

x

65
Q

What is meant by chemical equilibrium?

A

x

66
Q

State Le Chateliers Principle.

A

x

67
Q

Cobalt (II) chloride is dissolved in water, if the forward reaction is exothermic state the colour change observed when the reaction mixture is placed in hot water.

A

x

68
Q

Cobalt (II) chloride is dissolved in water, other than placing the mixture in ice mention one way of reversing the change caused by heating the mixture.

A

x

69
Q

The concentration of ethanoic acid (CH₃COOH) in a bottle of vinegar is given as 4.5% w/v. Find it’s concentration in moles/litre.

A

x

70
Q

A water sample was analysed and found to contain 9.6 p.p.m of oxygen (O₂). How many molecules of oxygen are in 250 cm³ of this sample?

A

x

71
Q

What is meant by the biochemical oxygen demand (BOD) of a water sample?

A

x

72
Q

Define reduction in terms of (i) electron transfer, (ii) change in oxidation number.

A

x

73
Q

Using oxidation numbers, identify which species is being oxidised and which species is being reduced in the following reactions. (8) MnO4− + Cl – + H+ Mn2+ + Cl2 + H2O Cr2O72– + S + H+ Cr2O3 + SO2 + OH–

A
74
Q

Hence, or otherwise, balance the equations.

A
75
Q

What is an ideal gas?

A

x

76
Q

6.6g of a gas was found to occupy a volume of 42cm³ at 64° C and a pressure of 100,000 Pa. use the equation of state for an ideal gas equation to calculate the number of moles of the gas present.

A

x

77
Q

6.6g of a gas was found to occupy a volume of 42cm³ at 64° C and a pressure of 100,000 Pa. use the equation of state for an ideal gas equation to calculate the relative molecular mass of the gas.

A

xx

78
Q

6.6g of a gas was found to occupy a volume of 42cm³ at 64° C and a pressure of 100,000 Pa. If the gas was identified as an alkane write its molecular formula.

A

x

79
Q

What is ozone.

A

x

80
Q

Use chemical equations to show how ozone may be formed in the stratosphere.

A

x

81
Q

What is the beneficial effect of the ozone layer?

A

x

82
Q

What are CFCs?

A

x

83
Q

State a use of CFCs. Explain how CFCs destroy the ozone layer.

A

x

84
Q

What is meant by the term addition polymer?

A

x

85
Q

What is meant by the term addition polymer? Draw the monomer used to form the following polymers

(i) Polychloroethene.
(ii) Polyphenylethene.

A

x

86
Q

What are the common names for the polymers (i) Polychloroethene. and (ii) Polyphenylethene. and give two uses of each.

A

x