Topic 6 Quantitative analysis, equilibrium, fuel cells Flashcards
1
Q
- What is the relative formula mass of magnesium oxide, MgO?
A
40
2
Q
- What is the relative formula mass of water, H2O?
A
18
3
Q
- What is the relative formula mass of carbon dioxide, CO2?
A
44
4
Q
- What is the relative formula mass of sulfuric acid, H2SO4?
A
98
5
Q
- What is the empirical formula of a compound with molecular formula C2H6?
A
CH3
6
Q
- What is the empirical formula of a compound with molecular formula C6H6?
A
CH
7
Q
- H What is the mass of 1 mole of sodium chloride, NaCl?
A
58.5 g
8
Q
- H What is the mass of 0.1 mole of sulfur dioxide, SO2?
A
6.4 g
9
Q
- What mass of water should be formed when 2 g of hydrogen reacts with 16 g of oxygen?
A
18 g
10
Q
- What mass of magnesium oxide should be formed when 2.4 g of magnesium reacts with 1.6 g of oxygen?
A
4.0 g
11
Q
- What is meant by the actual yield?
A
the actual amount of product formed in a reaction
12
Q
- What is meant by the theoretical yield?
A
the maximum mass of product calculated from the balanced equation
13
Q
- What is the formula for calculating percentage yield?
A
(actual yield/theoretical yield) × 100%
14
Q
- What is the percentage yield if the actual yield is 60 g and the theoretical yield is 100 g?
A
60%
15
Q
- What is the percentage yield if the actual yield is 5.5 g and the theoretical yield is 10 g?
A
55%
16
Q
- What is the percentage yield if the actual yield is 15 g and the theoretical yield is 20 g?
A
75%
17
Q
- What is the percentage yield if the actual yield is 0.1 g and the theoretical yield is 0.5 g?
A
20%
18
Q
- Give one reason why the actual yield is less than the theoretical yield.
A
incomplete reaction, practical losses or competing reactions
19
Q
- What is the relative formula mass of calcium hydroxide, Ca(OH)2?
A
74
20
Q
- What is the relative formula mass of magnesium nitrate, Mg(NO3)2?
A
148
21
Q
- What is meant by a solute?
A
a substance that dissolves in a liquid
22
Q
- What is meant by a solvent?
A
the liquid that dissolves the solute
23
Q
- How many cm3 are there in 1 dm3?
A
1000
24
Q
- What is the concentration, in g dm-3, of 100 cm3 of a solution containing 2 g of solute?
A
20 g dm-3
25
25. What is the concentration, in g dm-3, of 500 cm3 of a solution containing 5 g of solute?
5 g dm-3
26
26. What is the concentration, in g dm?3, of 250 cm3 of a solution containing 4 g of solute?
4 g dm-3
27
27. What is the amount, in moles, of hydrochloric acid, HCl, in 36.5 g?
1 mol
28
28. What is the amount, in moles, of sodium hydroxide, NaOH, in 20 g?
0.5 mol
29
29. What is the concentration of hydrochloric acid, in mol dm-3, if the concentration is 36.5 g dm-3?
1 (mol dm-3)
30
30. What is the concentration of sodium hydroxide in mol dm-3, if the concentration is 20 g dm-3?
(0.5 (mol dm-3))
31
31. What are the two substances formed when an acid reacts with an alkali?
salt and water
32
32. What type of reaction takes place when an acid reacts with an alkali?
neutralisation
33
33. Is potassium hydroxide an acid, an alkali or a salt?
alkali
34
34. Is sodium sulfate an acid, an alkali or a salt?
salt
35
35. What is used to show that a solution is acidic, alkaline or neutral?
an indicator
36
36. What colour is phenolphthalein in an acidic solution?
colourless
37
37. What colour is methyl orange in an alkaline solution?
yellow
38
38. What measuring instruments are used to measure the accurate volumes of acid and alkali in a titration?
burette and pipette
39
39. **H** How many moles of solute are there in 2 dm3 of 0.1 mol dm-3 hydrochloric acid?
0.2 mol
40
40. **H** How many moles of solute are there in 100 cm3 of 0.1 mol dm-3 hydrochloric acid?
0.01 mol
41
41. What is the abbreviation used for the mole, the unit for amount of substance?
mol
42
42. How many particles are there in 1 mole of particles?
6.02 × 1023
43
43. The mass of 1 mole of carbon atoms is 12 g. What is the mass of 2 moles of carbon atoms?
24 g
44
44. 2 g of hydrogen gas contains 1 mole of hydrogen molecules. How many moles are there in 1 g of hydrogen molecules?
0.5 mol
45
45. Each water molecule contains three atoms. How many moles of atoms are there in 2 moles of water molecules?
6 mol
46
46. The relative formula mass of chlorine gas is 71. What is the mass of 1 mole of chlorine gas?
71 g
47
47. What happens to the volume of a gas if its pressure is increased but its temperature is kept the same?
volume decreases
48
48. What happens to the volume of a gas if its temperature is increased but its pressure is kept the same?
volume increases
49
49. What is 100 dm3 in cm3?
100 000 cm3
50
50. 0.5 mol of salt is dissolved in 2 dm3 of water. What is the concentration of the solution?
0.25 mol dm–3
51
51. What are the chemical symbols for the elements nitrogen, potassium and phosphorus?
N, P, K
52
52. What two gases react together to produce ammonia in the Haber process?
nitrogen, hydrogen
53
53. What temperature is used in the Haber process?
450 °C
54
54. What pressure is used in the Haber process?
200 atmospheres
55
55. Why is iron used in the Haber process?
It is the catalyst/it makes the reaction go faster.
56
56. Is ammonium sulfate soluble or insoluble in water?
soluble
57
57. Name the acid needed to produce ammonium nitrate.
nitric acid
58
58. Name the acid needed to produce ammonium sulfate.
sulfuric acid
59
59. What method produces a solution containing only salt and water from an acid and alkali?
titration/neutralisation
60
60. There is only one product in the Haber process. What is the atom economy of the process?
100%
61
61. Write down or describe the symbol used for reversible reactions.
double headed arrow
62
62. Do the reactions keep going when a reversible reaction reaches equilibrium?
yes
63
63. Do the concentrations of the reacting substances change at equilibrium?
no
64
64. What compound is manufactured in the Haber process?
ammonia
65
65. If the temperature is increased in a dynamic equilibrium, does the position move towards the endothermic reaction or towards the exothermic reaction?
towards the endothermic reaction
66
66. If the pressure is increased in a dynamic equilibrium involving gases, does the position move towards the fewest number of moles of gas?
yes
67
67. Compared with the theoretical yield, is the actual yield of product usually less, the same or more?
less
68
68. What happens to the rate of a reaction if the temperature is increased?
it increases
69
69. What happens to the rate of a reaction if a suitable catalyst is added?
it increases
70
70. Does a catalyst get used up in the reaction it catalyses?
no
71
71. Which is more reactive, zinc or iron?
zinc
72
72. Name the ion released by acids when they dissolve in water.
hydrogen/H+
73
73. Name the product formed when hydrogen reacts with oxygen.
water
74
74. What charged particles move through the liquid during electrolysis?
ions
75
75. In what type of reaction is energy transferred to the surroundings?
exothermic
76
76. What is the unit for electrical potential difference?
volt/V
77
77. In electrolysis, what do we call the ionic compounds that are decomposed?
electrolytes
78
78. What is the approximate voltage of a typical AA battery?
1.5 V
79
79. What fuel is used in a hydrogen–oxygen fuel cell?
hydrogen
80
80. What is oxidation?
reaction with oxygen/gain of oxygen/loss of electrons
81
81. Fertilisers typically contain three essential elements. What are they?
Fertilisers help to replace nitrogen, phosphorus and potassium in the soil, which are used by growing plants.
82
82. Which essential elements are provided by the fertiliser potassium nitrate, KNO3?
Potassium nitrate contains potassium and nitrogen.
83
83. What fertiliser can be made by neutralising potassium hydroxide with phosphoric acid?
Potassium phosphate is made by reacting potassium hydroxide with phosphoric acid.
84
What is the name of the process to make ammonia and what is the balanced reaction?
The Habour Process
N2 + 3H2 ⇌ 2NH3
85
85. Which of the following properties is essential for compounds used in fertilisers?
Compounds used in fertilisers need to be soluble in water so they can be absorbed through their roots.
86
86. Which of these salts could be made from ammonia and nitric acid?
NH4NO3 could be made from ammonia (NH3) and nitric acid (HNO3).
87
87. Which two reactants are needed to make ammonium sulfate in the laboratory?
Ammonia + sulfuric acid → ammonium sulfate.
88
88. A student has prepared a solution of ammonium sulfate. What should she do to prepare dry crystals of ammonium sulfate?
Evaporation will remove the water and leave behind crystals of ammonium sulfate.
89
89. Why is the industrial manufacture of fertilisers carried out using a continuous process rather than a batch process?
The continuous process involves the continual adding of reactants as products are removed. This is more suited to the production of larger quantities of chemicals than batch processes.
90
90. What is the effect of adding a catalyst to a reversible reaction?
Catalysts decreases the time taken to reach equilibrium as they speed up the forward and reverse reactions. Catalysts have no effect on the yield.
91
91. In the Haber process, decreasing the temperature increases the yield of the reaction. Why is a very low temperature not used?
Rate decreases as temperature decreases, so the reaction would be too slow. The reactant gases involved would not condense unless the temperature was very low indeed.
92
92. Why is producing ethanol from ethene not sustainable?
Ethene is obtained by cracking fractions from crude oil, so there is a finite supply of the raw material for ethene. Ethene does not cause ozone depletion.
93
93. Which of these factors does not affect the choice of reaction pathway in an industrial chemical manufacturing process?
The relative formula mass of the products does not effect the choice of reaction pathway. The uses of by-products is important a forming valuable by-products can improve profitability of the process.
94
94. Which of the following is a method used to produce ethanol from sugars?
Fermentation is used to produce ethanol from sugars.
95
92. Chemical cells produce a voltage. When do they stop producing a voltage and 'go flat'?
When one of the reactants has run out
96
93. Which is a disadvantage for using a hydrogen-oxygen fuel cell in a space station?
Fuel cells do not generate much heat due to their efficiency, so they are not useful for keeping the space station warm. They do have a small and compact size.
97
97. Where can hydrogen be obtained from on the space station without transporting it from Earth?
Water can be electrolysed using electricity from solar cells. This produces hydrogen and oxygen. Plants do not generate hydrogen.
98
98. In the space station, why can you not rely on solar cells all the time?
Solar cells only work when sunlight falls on them, and this is not always the case on the space station. Solar cells are usually very reliable.
