IBDP Official Exam Material
FREE Past paper Questions by Topic
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Topic 1: Stoichiometric relationships
For both SL and HL students
1. [1 mark]
How many oxygen atoms are present in 0.0500 mol Ba(OH)2•8H2O?
NA = 6.02 × 1023
A. 3.01 × 1023
B. 6.02 × 1023
C. 3.01 × 1024
D. 6.02 × 1024
2. [1 mark]
What is the change of state for a gas to a solid?
A. Condensation
B. Deposition
C. Freezing
D. Sublimation
3. [1 mark]
How many moles of carbon dioxide are produced by the complete combustion of 7.0 g of ethene, C2H4 (g)?
Mr = 28
A. 0.25
B. 0.5
C. 0.75
D. 1.0
4. [1 mark]
Which is a possible empirical formula for a substance with Mr = 42?
A. CH
B. CH2
C. C3H6
D. C3H8
5. [1 mark]
0.2 mol of sodium hydrogencarbonate is decomposed by heating until constant mass.
2 NaHCO3 (s) → Na2CO3 (s) + H2O (g) + CO2 (g)
How many moles of gas are produced?
A. 0.1
B. 0.2
C. 0.3
D. 0.4
6. [1 mark]
Which sample contains the fewest moles of HCl?
NA = 6.02 × 1023 mol–1.
Molar volume of an ideal gas at STP = 22.7 dm3 mol–1.
A. 10.0 cm3 of 0.1 mol dm–3 HCl (aq)
B. 6.02 × 1024 molecules of HCl (g)
C. 0.365 g of HCl (g)
D. 2.27 dm3 of HCl (g) at STP
7. [1 mark]
What is the molecular formula of a compound with an empirical formula of CHO2 and a relative molecular mass of 90?
A. CHO2
B. C2H2O4
C. C3H6O3
D. C4H10O2
8. [1 mark]
8.8 g of an oxide of nitrogen contains 3.2 g of oxygen. What is the empirical formula of the compound?
A. N2O5
B. N2O
C. NO2
D. NO
9. [1 mark]
What is the concentration of chloride ions, in mol dm−3, in a solution formed by mixing 200 cm3 of 1 mol dm−3 HCl with 200 cm3 of 5 mol dm−3 NaCl?
A. 1
B. 2
C. 3
D. 6
10. [1 mark]
30 g of an organic compound produces 44 g CO2 and 18 g H2O as the only combustion products. Which of the following is the empirical formula for this compound?
Mr CO2 = 44 Mr H2O = 18
A. CH2
B. CH3
C. CHO
D. CH2O
11. [1 mark]
Which graph represents the relationship between the amount of gas, n, and the absolute temperature, T, with all other variables in the ideal gas equation, PV = nRT, held constant?
12. [1 mark]
Which equation represents the deposition of iodine?
A. I2 (g) → I2 (l)
B. I2 (g) → I2 (s)
C. I2 (l) → I2 (g)
D. I2 (s) → I2 (g)
13. [1 mark]
What is the coefficient for H+ when the equation below is balanced?
__Pb (s) + __NO3− (aq) + __H+ (aq) → __Pb2+ (aq) + __NO (g) + __H2O (l)
A. 2
B. 4
C. 6
D. 8
14. [1 mark]
2.67 g of lead (II) carbonate is decomposed by heating until constant mass.
PbCO3 (s) → PbO (s) + CO2 (g)
What is the final mass of solid?
A. 0.44 g
B. 2.23 g
C. 2.67 g
D. 3.11 g
15. [1 mark]
0.02 mol of zinc is added to 10.0 cm3 of 1.0 mol dm–3 hydrochloric acid.
Zn (s) + 2HCl (aq) → ZnCl2 (aq) + H2 (g)
How many moles of hydrogen are produced?
A. 0.005
B. 0.01
C. 0.02
D. 0.04
16a. [1 mark]
Ammonium nitrate, NH4NO3, is used as a high nitrogen fertilizer.
Calculate the percentage by mass of nitrogen in ammonium nitrate. Use section 6 of the data booklet.
16b. [1 mark]
State, with a reason, whether the ammonium ion is a Brønsted-Lowry acid or base.
16i. [1 mark]
Solid ammonium nitrate can decompose to gaseous dinitrogen monoxide and liquid water.
Write the chemical equation for this decomposition.
16j. [2 marks]
Calculate the volume of dinitrogen monoxide produced at STP when a 5.00 g sample of ammonium nitrate decomposes. Use section 2 of the data booklet.
17. [2 marks]
Lignite, a type of coal, contains about 0.40 % sulfur by mass.
Calculate the amount, in mol, of sulfur dioxide produced when 500.0 g of lignite undergoes combustion.
S (s) + O2 (g) → SO2 (g)
18. [1 mark]
Write an equation that shows how sulfur dioxide can produce acid rain.
19a. [1 mark]
When heated in air, magnesium ribbon reacts with oxygen to form magnesium oxide.
Write a balanced equation for the reaction that occurs.
19b. [1 mark]
State the block of the periodic table in which magnesium is located.
19c. [1 mark]
Identify a metal, in the same period as magnesium, that does not form a basic oxide.
19d. [1 mark]
The reaction in (a)(i) was carried out in a crucible with a lid and the following data was recorded:
Mass of crucible and lid = 47.372 ±0.001 g
Mass of crucible, lid and magnesium ribbon before heating = 53.726 ±0.001 g
Mass of crucible, lid and product after heating = 56.941 ±0.001 g
Calculate the amount of magnesium, in mol, that was used.
19e. [2 marks]
Determine the percentage uncertainty of the mass of product after heating.
19f. [2 marks]
Assume the reaction in (a)(i) is the only one occurring and it goes to completion, but some product has been lost from the crucible. Deduce the percentage yield of magnesium oxide in the crucible.
19g. [1 mark]
When magnesium is burnt in air, some of it reacts with nitrogen to form magnesium nitride according to the equation:
3 Mg (s) + N2 (g) → Mg3N2 (s)
Evaluate whether this, rather than the loss of product, could explain the yield found in (b)(iii).
19h. [1 mark]
Suggest an explanation, other than product being lost from the crucible or reacting with nitrogen, that could explain the yield found in (b)(iii).
19i. [1 mark]
The presence of magnesium nitride can be demonstrated by adding water to the product.
It is hydrolysed to form magnesium hydroxide and ammonia.
Calculate coefficients that balance the equation for the following reaction.
__ Mg3N2 (s) + __ H2O (l) → __ Mg(OH)2 (s) + __ NH3 (aq)
19m. [1 mark]
Some nitride ions are 15N3–.
State the term that describes the relationship between 14N3– and 15N3–.
19n. [1 mark]
The nitride ion and the magnesium ion are isoelectronic (they have the same electron configuration). Determine, giving a reason, which has the greater ionic radius.
19o. [2 marks]
Suggest two reasons why atoms are no longer regarded as the indivisible units of matter.
20j. [2 marks]
Determine the concentration, in mol dm–3, of the solution formed when 900.0 dm3 of NH3 (g) at 300.0 K and 100.0 kPa, is dissolved in water to form 2.00 dm3 of solution. Use sections 1 and 2 of the data booklet.
20k. [1 mark]
Calculate the concentration of hydroxide ions in an ammonia solution with pH = 9.3. Use sections 1 and 2 of the data booklet.
21a. [1 mark]
Lithium reacts with water to form an alkaline solution.
Determine the coefficients that balance the equation for the reaction of lithium with water.
21b. [2 marks]
A 0.200 g piece of lithium was placed in 500.0 cm3 of water.
Calculate the molar concentration of the resulting solution of lithium hydroxide.
21c. [2 marks]
Calculate the volume of hydrogen gas produced, in cm3, if the temperature was 22.5 °C and the pressure was 103 kPa. Use sections 1 and 2 of the data booklet.
21d. [1 mark]
Suggest a reason why the volume of hydrogen gas collected was smaller than predicted.
21e. [1 mark]
The reaction of lithium with water is a redox reaction. Identify the oxidizing agent in the reaction giving a reason.
21f. [2 marks]
Describe two observations that indicate the reaction of lithium with water is exothermic.
22d. [1 mark]
Ammonium nitrate is neutralized with sodium hydroxide. Write the equation for the reaction.
22r. [2 marks]
Calculate the volume of dinitrogen monoxide produced at STP when a 5.00 g sample of ammonium nitrate decomposes. Use section 2 of the data booklet.
23. [1 mark]
What is the number of hydrogen atoms in 2.00 moles of Ca(HCO3)2?
Avogadro’s constant, L or NA: 6.02 × 1023 mol−1
A. 2.00
B. 4.00
C. 1.20 × 1024
D. 2.41 × 1024
24. [1 mark]
Which statement describes all homogeneous mixtures?
A. Any sample has the same ratio of the components.
B. The components are covalently bonded together.
C. The components cannot be easily separated.
D. The mixture needs a specific ratio of components to form.
25. [1 mark]
What volume of oxygen, in dm3 at STP, is needed when 5.8 g of butane undergoes complete combustion?
2C4H10 g+13O2 g→8CO2 g+10H2O l
A. 2×5.812.01×4+1.01×10×13×22.7
B. 5.812.01×4+1.01×10×132×22.7
C. 5.812.01×4+1.01×10×213×22.7
D. 5.812.01×4+1.01×10×132×22.71000
26. [1 mark]
What is the coefficient of HCl (aq) when the equation is balanced using the smallest possible whole numbers?
__CuO (s)+ __HCl (aq) → __CuCl2 (aq) + __H2O (l)
A. 1
B. 2
C. 3
D. 4
27. [1 mark]
0.20 mol of magnesium is mixed with 0.10 mol of hydrochloric acid.
Mg (s)+2HCl (aq)→MgCl2 (aq)+H2 (g)
Which is correct?
28. [1 mark]
Which amount, in mol, of sodium chloride is needed to make 250 cm3 of 0.10 mol dm−3 solution?
A. 4.0 × 10−4
B. 0.025
C. 0.40
D. 25
29. [6 mark]
An organic compound, Y, has the following composition by mass.
It is 62% by mass carbon and 24.1% by mass nitrogen, with the remainder being hydrogen.
(a) Determine the percentage by mass of hydrogen, and the empirical formula of Y. (3)
(b) Define the term relative molecular mass. (2)
(c) The M of the compound Y is 116.
Determine the molecular formula of Y. (1)
30. [6 mark]
The reduction of iron ore, hematite, takes place in the blast furnace for the extraction of iron.
The equation for the reaction is: 2Fe O (s) + 3C (s) → 4Fe (s) + 3CO (g)
A mixture of 30.0 kg of iron(III) oxide and 5.00 kg of pure carbon was heated until no further reaction took place.
(a) Calculate the maximum mass of iron that can be obtained from this reaction. Give the answer to 3 significant figures. (5)
(b) The actual yield of iron was 14.0 kg.
Calculate the % yield of iron. (1)
If you need the markscheme, including the examiners' reports for each question, and more exam and teaching materials on this topic, contact me through the contact page