1.4 Past Paper Questions

Topic1 Questions

1. What amount of Oxygen, O₂, (in moles) contains 1.8×10²² molecules?

A. 0.0030

B. 0.030

C. 0.30

D. 3.0 (Total 1 mark)

2. Which compound has the empirical formula with the greatest mass?

A. C₂H₆

B. C₄H₁₀

C. C₅H₁₀

D. C₆H₆ (Total 1 mark)

3. __C₂H_2(g) + __O_2(g) → __ CO_2(g) + __ H₂O_(g)

When the equation above is balanced, what is the coefficient for Oxygen?

A. 2

B. 3

C. 4

D. 5 (Total 1 mark)

4. 3.0 dm³ of SO₂ is reacted with 2.0 dm³of Oxygen according to the equation.

2SO_2(g) + O_2(g) → 2SO_3(g)

What volume of Sulphur Trioxide (in dm³) is formed? (Assume the reaction goes to completion and all gases are measured at the same temperature and pressure.)

A. 5.0

B. 4.0

C. 3.0

D. 2.0

(Total 1 mark)

5. What happens to the volume of a fixed mass of gas when its pressure & temperature (in Kelvin) are both doubled?

A. It will not change.

B. It will increase.

C. It will decrease.

D. The change cannot be predicted.

(Total 1 mark)

6. What amount (in moles) is present in 2.0 g of Sodium Hydroxide, NaOH?

A. 0.050

B. 0.10

C. 20

D. 80

(Total 1 mark)

7. A hydrocarbon contains 90% by mass of Carbon. What is its empirical formula?

A. CH₂

B. C₃H₄

C. C₇H₁₀

D. C₉H₁₀

(Total 1 mark)

8. Copper can react with Nitric Acid as follows.

3Cu +_HNO₃ --> _Cu(NO₃)₂ +_H₂O + _NO

What is the coefficient for HNO₃ when the equation is balanced?

A. 4

B. 6

C. 8

D. 10

(Total 1 mark)

9. Lithium Hydroxide reacts with Carbon Dioxide as follows.

2LiOH + CO₂ → Li₂CO₃ + H₂O

What mass (in grams) of Lithium Hydroxide is needed to react with 11 g of CO₂?

A. 6

B. 12

C. 24

D. 48

(Total 1 mark)

10. Which change in conditions would increase the volume of a fixed mass of gas?

(Total 1 mark)

11. How many Hydrogen atoms are contained in one mole of Ethanol, C₂H₅OH?

A. 5

B. 6

C. 1.0×10²³

D. 3.6×10²⁴

(Total 1 mark)

12. The percentage by mass of the elements in a compound is

C = 72%, H = 12%, O = 16%.

What is the mole ratio of C:H in the empirical formula of this compound?

A. 1 : 1

B. 1 : 2

C. 1 : 6

D. 6 : 1

(Total 1 mark)

13. What is the coefficient for O_2(g) when the equation below is balanced?

__C₃H_8(g) + __O_2(g) → __CO_2(g) + __H₂O_(g)

A. 2

B. 3

C. 5

D. 7

(Total 1 mark)

14. What amount of NaCl (in moles) is required to prepare 250 cm³ of a 0.200 mol dm^–3 solution?

A. 50.0

B. 1.25

C. 0.800

D. 0.0500

(Total 1 mark)

15. For which set of conditions does a fixed mass of an ideal gas have the greatest volume?

(Total 1 mark)

16. Which of the following contains the greatest number of molecules?

A. 1 g of CH₃Cl

B. 1 g of CH₂Cl₂

C. 1 g of CHCl₃

D. 1 g of CCl₄

(Total 1 mark)

17. Which of the following compounds has/have the empirical formula CH₂O?

I. CH₃COOH

II. C₆H₁₂O₆

III. C₁₂H₂₂O₁₁

A. II only

B. III only

C. I and II only

D. II and III only

(Total 1 mark)

18. Assuming complete reaction, what volume of 0.200 mol dm^-3 HCl(aq) is required to neutralize 25.0 cm³ of 0.200 mol dm^-3Ba(OH)_2(aq)?

A. 12.5 cm3

B. 25.0 cm3

C. 50.0 cm3

D. 75.0 cm3

(Total 1 mark)

19. Under what conditions would one mole of Methane gas, CH₄, occupy the smallest volume?

A. 273 K and 1.01×10⁵ Pa

B. 273 K and 2.02×10⁵ Pa

C. 546 K and 1.01×10⁵ Pa

D. 546 K and 2.02×10⁵ Pa

(Total 1 mark)

20. The temperature in Kelvin of 2.0 dm³ of an ideal gas is doubled and its pressure is increased by a factor of four. What is the final volume of the gas?

A. 1.0 dm³

B. 2.0 dm³

C. 3.0 dm³

D. 4.0 dm³

(Total 1 mark)

21. Which is a correct definition of the term empirical formula?

A. formula showing the numbers of atoms present in a compound

B. formula showing the numbers of elements present in a compound

C. formula showing the actual numbers of atoms of each element in a compound

D. formula showing the simplest ratio of numbers of atoms of each element in a compound

(Total 1 mark)

22. The reaction of Ethanal and Oxygen can be represented by the unbalanced equation below.

__ CH₃CHO + __ O₂ → __ CO₂ + __ H₂O

When the equation is balanced using the smallest possible integers, what is the coefficient for O₂?

A. 3

B. 4

C. 5

D. 6

(Total 1 mark)

23. The equation for the complete combustion of Butane is

2C₄H₁₀ + 13O₂ → 8CO₂ + 10H₂O

What is the amount (in mol) of Carbon Dioxide formed by the complete combustion of three moles of Butane?

A. 4

B. 8

C. 12

D. 24

(Total 1 mark)

24. Which solution contains the greatest amount (in mol) of solute?

A. 10.0 cm³ of 0.500 mol dm^–3 NaCl

B. 20.0 cm³ of 0.400 mol dm^–3 NaCl

C. 30.0 cm³ of 0.300 mol dm^–3 NaCl

D. 40.0 cm³ of 0.200 mol dm^–3 NaCl

(Total 1 mark)

25. A fixed mass of an ideal gas has a volume of 800 cm³ under certain conditions. The pressure (in kPa) and temperature (in K) are both doubled. What is the volume of the gas after these changes with other conditions remaining the same?

A. 200 cm³

B. 800 cm³

C. 1600 cm³

D. 3200 cm³

(Total 1 mark)

26. The complete oxidation of propane produces Carbon Dioxide and Water as shown below.

C₃H₈ + __O₂ --> __CO₂ + __H₂O

What is the total of the coefficients for the products in the balanced equation for 1 mole of Propane?

A. 6

B. 7

C. 12

D. 13

(Total 1 mark)

27. The relative molecular mass (Mr) of a compound is 60. Which formulas are possible for this compound?

I. CH₃CH₂CH₂NH₂

II. CH₃CH₂CH₂OH

III. CH₃CH(OH)CH₃

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

(Total 1 mark)

28. Which sample has the least number of atoms?

A. 1 mol of H₂SO₄

B. 1 mol of CH₃COOH

C. 2 mol of H₂O₂

D. 2 mol of NH₃

(Total 1 mark)

29. Avogadro’s constant has the same value as the number of

A. molecules in 1 mol of solid Iodine.

B. atoms in 1 mol of Chlorine gas.

C. ions in 1 mol of solid Potassium Bromide.

D. protons in 1 mol of Helium gas.

(Total 1 mark)

30. What is the total of all the coefficients in the balanced equation for the reduction of 1 mol of MnO₄^–?

__ MnO₄^–+__H⁺ + __ e– -->__Mn²⁺ + __H₂O

A. 5

B. 9

C. 17

D. 19

(Total 1 mark)

31. Which contains the same number of ions as the value of Avogadro’s constant?

A. 0.5 mol NaCl

B. 0.5 mol MgCl₂

C. 1.0 mol Na₂O

D. 1.0 mol MgO

(Total 1 mark)

32. A reaction occurring in the extraction of Lead from its ore can be represented by this unbalanced equation:

__ PbS + __O₂--> __ PbO + __ SO₂

When the equation is balanced using the smallest possible whole numbers, what is the coefficient for O₂?

A. 1

B. 2

C. 3

D. 4

(Total 1 mark)

33. The equation for a reaction occurring in the synthesis of Methanol is

CO2 + 3H₂ --> CH₃OH + H₂O

What is the maximum amount of Methanol that can be formed from 2 mol of Carbon Dioxide and 3 mol of Hydrogen?

A. 1 mol

B. 2 mol

C. 3 mol

D. 5 mol

(Total 1 mark)

34. Which solution contains 0.1 mol of Sodium Hydroxide?

A. 1 cm³ of 0.1 mol dm^–3 NaOH

B. 10 cm³ of 0.1 mol dm^–3 NaOH

C. 100 cm³ of 1.0 mol dm^–3 NaOH

D. 1000 cm³ of 1.0 mol dm^–3 NaOH

(Total 1 mark)

35. A cylinder of gas is at a pressure of 40 kPa. The volume and temperature (in K) are both doubled. What is the pressure of the gas after these changes?

A. 10 kPa

B. 20 kPa

C. 40 kPa

D. 80 kPa

(Total 1 mark)

36. Which of the following quantities has units?

A. Relative atomic mass

B. Relative molecular mass

C. Molar mass

D. Mass number

(Total 1 mark)

37. The empirical formula of a compound is C₂H₄O. Which molecular formulas are possible for this compound?

I. CH₃COOH

II. CH₃CH₂CH₂COOH

III. CH₃COOCH₂CH₃

A. I and II only

B. I and III only

C. II and III only

D. I, II and III

(Total 1 mark)

38. Calcium Carbonate decomposes on heating as shown below.

CaCO₃ --> CaO + CO₂

When 50 g of Calcium Carbonate are decomposed, 7 g of Calcium Oxide are formed. What is the percentage yield of Calcium Oxide ?

A. 7%

B. 25%

C. 50%

D. 75%

(Total 1 mark)

39. Sodium reacts with Water as shown below.

__ Na + __ H₂O --> __ NaOH + __ H₂

What is the total of all the coefficients when the equation is balanced using the smallest possible whole numbers?

A. 3

B. 4

C. 6

D. 7

(Total 1 mark)

40. What is the total number of ions present in the formula, Al₂(SO₄)₃?

A. 2

B. 3

C. 5

D. 6

(Total 1 mark)

41. A 4 g sample of Sodium Hydroxide, NaOH, is dissolved in water and made up to 500 cm³ of aqueous solution. What is the concentration of the resulting solution?

A. 0.1 mol dm^–3

B. 0.2 mol dm^–3

C. 0.5 mol dm^–3

D. 1.0 mol dm^–3

(Total 1 mark)

42. Methane, CH₄, burns in Oxygen gas to form Carbon Dioxide and water. How many moles of Carbon Dioxide will be formed from 8.0 g of Methane?

A. 0.25

B. 0.50

C. 1.0

D. 2.0

(Total 1 mark)

43. What is the empirical formula of a compound containing 50% by mass of element X (Ar = 20) and 50% by mass of element Y (Ar = 25)?

A. XY

B. X₃Y₂

C. X₄Y₅

D. X₅Y₄

(Total 1 mark)

44. What volume of 0.200 mol dm^–3 Potassium Hydroxide solution (KOH_(aq)), is required to neutralize 25.0 cm³ of 0.200 mol dm^–3 aqueous sulfuric acid, (H₂SO_4(aq))?

A. 12.5 cm³

B. 25.0 cm³

C. 50.0 cm³

D. 75.0 cm³

(Total 1 mark)

45. Consider the following reaction.

N_2(g) + 3H_2(g) --> 2NH_3(g)

If the reaction is made to go to completion, what volume of Ammonia (in dm³) can be prepared from 25 dm³ of Nitrogen and 60 dm³ of Hydrogen? All volumes are measured at the same temperature and pressure.

A. 40

B. 50

C. 85

D. 120

(Total 1 mark)

46. The temperature in Kelvin of 1.0 dm³ of an ideal gas is doubled and its pressure is tripled. What is the final volume of the gas in dm³?

A. 1/3

B. 2/3

C. 3/2

D. 1/6

(Total 1 mark)

47. On complete combustion, a sample of a hydrocarbon compound produces 1.5 mol of Carbon Dioxide and 2.0 mol of Water. What is the molecular formula of this hydrocarbon?

A. C₂H₂

B. C₂H₄

C. C₃H₄

D. C₃H₈

(Total 1 mark)

48. When excess BaCl_2(aq) was added to a sample of Fe(NH₄)₂(SO₄)_2(aq)to determine the amount in moles of sulfate present, 5.02×10^–3 mol of BaSO₄ was obtained. How many moles of Sulphate ions and Iron ions were in the sample of Fe(NH₄)₂(SO₄)₂?

(Total 1 mark)

49. What volume of 0.500 mol dm^–3Sulphuric Acid solution is required to react completely with 10.0 g of Calcium Carbonate according to the equation below?

CaCO_3(s) + H₂SO_4(aq) --> CaSO_4(aq) + H₂O_(l) + CO_2(g)

A. 100 cm³

B. 200 cm³

C. 300 cm³

D. 400 cm³

(Total 1 mark)

50. Which expression gives the amount (in mol) of a substance, if the mass is given in grams?

A. Mass/Molar Mass

B. Molar Mass/ Mass

C. 1/Molar Mass

D. Mass × Molar Mass

(Total 1 mark)

51. What is the total number of atoms in 0.20 mol of Propanone, CH₃COCH₃?

A. 1.2×10²²

B. 6.0×10²³

C. 1.2×10²⁴

D. 6.0×10²⁴

(Total 1 mark)

52. When the equation below is balanced for 1 mol of C₃H₄, what is the coefficient for O₂?

C₃C₄ + ___O₂ --> ___CO₂ + ___H₂O

A. 2

B. 3

C. 4

D. 5

(Total 1 mark)

53. Ethyne, C₂H₂, reacts with oxygen according to the equation below. What volume of Oxygen (in dm³) reacts with 0.40 dm³ of C₂H₂?

2C₂H_2(g) + 5O_2(g) --> 4CO_2(g)+ 2H₂O_(g)

A. 0.40

B. 0.80

C. 1.0

D. 2.0

(Total 1 mark)

55. What is the coefficient for H⁺ when the redox equation below is balanced?

__Ag_(s) + __NO₃^–_(aq)+__H⁺_(aq) --> __Ag⁺_(aq) +__NO_(g) + __H₂O_(l)

A. 1

B. 2

C. 3

D. 4

(Total 1 mark)

56. How many Hydrogen atoms are in one mole of Ethanol, C₂H₅OH?

A. 1.00×10²³

B. 3.61×10²⁴

C. 5.00

D. 6.00

(Total 1 mark)

57. What is the coefficient for H₂SO_4(aq) when the following equation is balanced, using the smallest possible integers?

__Mg₃N_2(s) + __H₂SO_4(aq) → __MgSO_4(aq) + __(NH₄)₂SO_4(aq)

A. 1

B. 3

C. 4

D. 7

(Total 1 mark)

58. Air bags in cars inflate when Sodium Azide decomposes to form Sodium and Nitrogen:

2NaN_3(s) → 2Na_(s) + 3N_2(g)

Calculate the amount, in moles, of Nitrogen gas produced by the decomposition of 2.52 mol of NaN_3(s).

A. 1.68

B. 2.52

C. 3.78

D. 7.56

(Total 1 mark)

59. What volume, in cm³, of 0.200 mol dm^–3 HCl _(aq) is required to neutralize 25.0 cm³ of 0.200 mol dm^–3 Ba(OH)_2(aq)?

A. 12.5

B. 25.0

C. 50.0

D. 75.0

(Total 1 mark)

60. The relative molecular mass of Aluminium Chloride is 267 and its composition by mass is 20.3% Al and 79.7% Chlorine. Determine the empirical and molecular formulas of Aluminium Chloride.

……………………………………………………………………………………….........................................................................................................................................

(Total 4 marks)

61. Sodium reacts with Water as follows.

2Na_(s)+ 2H₂O_(l) --> 2NaOH_(aq) + H_2(g)

1.15 g of Sodium is allowed to react completely with Water. The resulting solution is diluted to 250 cm³. Calculate the concentration, in mol dm^–3, of the resulting Sodium Hydroxide solution.

……………………………………………………………………………………….........................................................................................................................................

(Total 3 marks)

62. (i) Calcium Carbonate is added to separate solutions of Hydrochloric Acid and Ethanoic Acid of the same concentration. State one similarity and one difference in the observations you could make.

……………………………………………………………………………………….........................................................................................................................................

……………………………………………………………………………………….................................................................................................................................... (2)

(ii) Write an equation for the reaction between Hydrochloric Acid and Calcium Carbonate.

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……………………………………………………………………………………….....................................................................................................................................(2)

(iii) Determine the volume of 1.50 mol dm^–3 Hydrochloric Acid that would react with exactly 1.25 g of Calcium Carbonate.

……………………………………………………………………………………….........................................................................................................................................

(iv) Calculate the volume of Carbon Dioxide, measured at 273 K and

1.01×10⁵ Pa, which would be produced when 1.25 g of Calcium Carbonate reacts completely with the Hydrochloric Acid.

……………………………………………………………………………………….........................................................................................................................................

……………………………………………………………………………………….....................................................................................................................................(2)

(Total 9 marks)

63. An organic compound, A, containing only the elements Carbon, Hydrogen and Oxygen was analysed.

(a) A was found to contain 54.5% C and 9.1%H by mass, the remainder being Oxygen. Determine the empirical formula of the compound.

(3)

(b) A 0.230 g sample of A, when vaporised, had a volume of 0.0785 dm³ at 95^oC and 102 kPa. Determine the relative molecular mass of A.

(3)

(c) Determine the molecular formula of A using your answers from parts (a) and (b).

……………………………………………………………………………………….........................................................................................................................................

………………………………………………………………………………………................................................................................................................................... (1)

(Total 7 marks)

64. An organic compound A contains 62.0%by mass of Carbon, 24.1% by mass of Nitrogen, the remainder being Hydrogen.

(i) Determine the percentage by mass of Hydrogen and the empirical formula of A.

……………………………………………………………………………………….........................................................................................................................................

……………………………………………………………………………………….................................................................................................................................... (3)

(ii) Define the term relative molecular mass.

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………………………………………………………………………………………................................................................................................................................... (2)

(iii) The relative molecular mass of A is 116. Determine the molecular formula of A.

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(Total 6 marks)

65. An organic compound A contains 62.0% by mass of Carbon, 24.1% by mass of Nitrogen, the remainder being Hydrogen.

(i) Determine the percentage by mass of Hydrogen and the empirical formula of A.

……………………………………………………………………………………….........................................................................................................................................

………………………………………………………………………………………................................................................................................................................ (3)

(ii) Define the term relative molecular mass.

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………………………………………………………………………………………............................................................................................................................. (2)

(iii) The relative molecular mass of A is 116. Determine the molecular formula of A.

……………………………………………………………………………………….........................................................................................................................................

………………………………………………………………………………………................................................................................................................................... (1)

(Total 6 marks)

66. Propane and Oxygen react according to the following equation.

C₃H_8(g) + 5O_2(g) --> 3CO_2(g) + 4H₂O_(g)

Calculate the volume of Carbon Dioxide and Water Vapour produced and the volume of oxygen remaining, when 20.0 dm³ of Propane reacts with 120.0 dm³ of Oxygen. All gas volumes are measured at the same temperature and pressure.

……………………………………………………………………………………….........................................................................................................................................

(Total 3 marks)

67. State and explain what would happen to the pressure of a given mass of gas when its absolute temperature and volume are both doubled.

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(Total 3 marks)

68. (i) Crocetin consists of the elements Carbon, Hydrogen and Oxygen. Determine the empirical formula of Crocetin, if 1.00 g of Crocetin forms 2.68 g of Carbon Dioxide and 0.657 g of Water when it undergoes complete combustion.

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……………………………………………………………………………………….................................................................................................................................... (6)

(ii) Determine the molecular formula of crocetin given that 0.300 mole of Crocetin has a mass of 98.5 g

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………………………………………………………………………………………................................................................................................................................... (2)

(Total 8 marks)

69. A solution containing Ammonia requires 25.0 cm³ of 0.100 mol dm^–3 Hydrochloric Acid to reach the equivalence point of a titration.

(i) Write an equation for the reaction of Ammonia with Hydrochloric Acid

(1)

(ii) Calculate the amount (in mol) of Hydrochloric Acid & Ammonia that react.

(2)

(iii) Calculate the mass of Ammonia in the solution.

(2)

(Total 5 marks)

70. A toxic gas, A, consists of 53.8% Nitrogen and 46.2% Carbon by mass. At 273 K and 1.01×10⁵ Pa, 1.048 g of A occupies 462 cm³. Determine the empirical formula of A.

Calculate the molar mass of the compound & determine its molecular structure.

(Total 3 marks)

71. An Oxide of Copper was reduced in a stream of Hydrogen as shown below.

After heating, the stream of gas was maintained until the apparatus had cooled.

The following results were obtained.

Mass of empty dish = 13.80 g

Mass of dish and contents before heating = 21.75 g

Mass of dish and contents after heating and leaving to cool = 20.15 g

(a) Explain why the stream of Hydrogen gas was maintained until the apparatus cooled.

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............................................................................................................................................................................................................................. (1)

(b) Calculate the empirical formula of the Oxide of Copper using the data above, assuming complete reduction of the Oxide.

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.............................................................................................................................................................................................................................. (3)

(c) Write an equation for the reaction that occurred.

...............................................................................................................................................................................................................................(1)

(d) State two changes that would be observed inside the tube as it was heated.

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(Total 7 marks)

72. Copper metal may be produced by the reaction of Copper (I) Oxide and Copper (I) Sulphide according to the below equation.

2Cu₂O + Cu₂S --> 6Cu + SO₂

A mixture of 10.0 kg of Copper (I) Oxide and 5.00 kg of Copper (I) Sulphide was heated until no further reaction occurred.

(a) Determine the limiting reagent in this reaction, showing your working.

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............................................................................................................................................................................................................................(3)

(b) Calculate the maximum mass of Copper that could be obtained from these masses of reactants.

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..............................................................................................................................................................................................................................(2)

(Total 5 marks)

73. The reaction below represents the reduction of Iron ore to produce Iron.

2Fe₂O₃ + 3C --> 4Fe + 3CO₂

A mixture of 30 kg of Fe₂O₃ and 5.0 kg of C was heated until no further reaction occurred.

Calculate the maximum mass of iron that can be obtained from these masses of reactants.

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(Total 5 marks)

74. 0.502 g of an alkali metal sulphate is dissolved in water and excess Barium Chloride solution, BaCl_2(aq) is added to precipitate all the sulfate ions as Barium Sulphate, BaSO_4(s). The precipitate is filtered and dried and weighs 0.672 g.

(a) Calculate the amount (in mol) of Barium Sulphate formed.

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(b) Determine the amount (in mol) of the alkali metal sulphate present.

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(c) Determine the molar mass of the alkali metal sulphate and state its units.

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(d) Deduce the identity of the alkali metal, showing your workings.

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..............................................................................................................................................................................................................................(2)

(e) Write an equation for the precipitation reaction, including state symbols.

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..............................................................................................................................................................................................................................(2)

(Total 9 marks)

75. 0.600 mol of Aluminium Hydroxide is mixed with 0.600 mol of Sulphuric Acid, and the following reaction occurs:

2Al(OH)_3(s) + 3H₂SO_4(aq) → Al₂(SO₄)_3(aq) + 6H₂O_(l)

(a) Determine the limiting reactant.

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..............................................................................................................................................................................................................................(2)

(b) Calculate the mass of Al₂(SO₄)₃produced.

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..............................................................................................................................................................................................................................(2)

(c) Determine the amount (in mol) of excess reactant that remains.

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..............................................................................................................................................................................................................................(1)