IBChemistryDPSLExam QuestionsHow Much, How Fast & How Far?How Much? The Amount of Chemical Change

How Much? The Amount of Chemical Change (DP IB Chemistry: SL): Exam Questions

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11 mark

When the following equation is balanced correctly, using the smallest whole number coefficients, which row represents the coefficients?

_ Mg3N2 (s)  + _H2O (l) → _Mg(OH)2 (aq) + _NH3 (aq)

 

Mg3N2

H2O

Mg(OH)2

NH3

A

1

6

3

2

B

1

3

3

1

C

2

6

2

2

D

2

6

3

2

    Choose your answer

    21 mark

    Which one of the following is the correct net ionic equation for the reaction between CaCl2 and AgNO3?

    • Ca2+ (aq) + 2AgNO3 (aq) → 2Ag+ (s) + Ca(NO3)2 (aq)

    • CaCl2 (aq) + 2Ag+ (aq) → 2AgCl (s) + Ca2+ (aq)

    • Ca2+ (aq) + 2NO3- (aq) → Ca(NO3)2 (aq)

    • Ag+ (aq) + Cl - (aq) → AgCl (s)

    Choose your answer

    31 mark

    Which one of the following is the correct net ionic equation for the reaction between NaC2H3O2 (aq) and HCl (aq)?

    • C2H3O2- (aq) + HCl (aq) → CCl - (aq) + 2H2 (aq) + CO2 (aq)

    • C2H3O2- (aq) + H+ (aq) →  HC2H3O2 (aq)

    • Na+ (aq) + Cl - (aq) → NaCl (aq)

    • NaC2H3O2 (aq) + H+ (aq) → HC2H3O2(aq) + Na+ (aq)

    Choose your answer

    41 mark

    Silicon reacts with chlorine gas to produce silicon chloride. 

    How many moles of chlorine gas are needed to react with 1 mole of silicon?

    • 2

    • 3

    • 4

    • 5

    Choose your answer

    51 mark

    When calcium carbonate is heated it decomposes according to the following equation

    CaCO3 (s)  → CaO(s) + CO2(g)

    If 6.00 g of calcium carbonate is heated and produces 2.73 g of calcium oxide, what is the percentage yield of calcium oxide? (Mr CaCO3 = 100.09; CaO = 56.08)

    • 18%

    • 81% 

    • 90%

    • 0.81%

    Choose your answer

    61 mark

    Hydrogen and chlorine react according to the following equation:

    H2 (g) + Cl2 (g) → 2HCl (g)

    When 1.5 moles of chlorine reacts with 2.0 moles of hydrogen, what will be the result?

    • 3.5 mol of HCl

    • 1.5 mol of HCl  and 0.5 mol of H2

    • 2.0 mol of HCl  and 0.5 mol of Cl2

    • 3.0 mol of HCl and 0.5 mol of H2

    Choose your answer

    71 mark

    25.0 cm3 of hydrochloric acid solutions reacts with 36.2 cm3 of 0.225 mol dm-3 sodium hydroxide solution.

    What is the concentration of the acid?

    • 0.33 mol dm–3

    • 0.16 mol dm–3

    • 1.55 x 10–4 mol dm–3

    • 3.26 x 10–4 mol dm–3

    Choose your answer

    81 mark

    A solution of sodium chloride is made by adding 300 cm3 of water to a flask containing 200 cm3 of 0.50 mol dm-3 sodium chloride. What is the concentration of the resulting solution?

    • 0.05 mol dm-3   

    • 0.1 mol dm-3 

    • 0.2 mol dm-3 

    • 0.3 mol dm-3 

    Choose your answer

    91 mark

    What is the number of molecules in 500 cm3 of oxygen under standard conditions?

    • 3.01 x 1023 

    • 1.33 x 1025

    • 2.73 x 1024

    • 1.33 x 1022

    Choose your answer

    101 mark

    Oxidation of ammonia by oxygen is the first step in the manufacture of nitric acid, which is used in the production of the synthetic material nylon.

    wO2 (g) + xNH3 (g) → yNO (g) + zH2O (g)

     Which values for w, x, y and z balance this equation?

     

    w

    x

    y

    z

    A

    5

    4

    4

    6

    B

    6

    4

    4

    5

    C

    6

    5

    5

    4

    D

    5

    6

    6

    4

      Choose your answer

      11 mark

      A 2.27 dm3 sample of nitrogen gas, measured under standard conditions, reacted with a large excess volume of hydrogen gas to produce ammonia. Only 20.0% of the nitrogen gas reacted to produce ammonia.

      What mass of ammonia was made?

      • 0.20 g

      • 0.34 g

      • 0.68 g

      • 1.36 g

      Choose your answer

      21 mark

      When 0.10 mol of chlorine gas, Cl2, reacts with excess cold sodium hydroxide, sodium chlorate(I) is formed as one of the products according to the equation:

      Cl2 (g) + 2NaOH (aq) → NaCl (aq) + NaClO (aq) + H2O (l)

      What mass of sodium chlorate(I), NaClO, is formed?

      • 3.54 g

      • 7.44 g

      • 14.8 g

      • 26.6 g

      Choose your answer

      31 mark

      When heated, anhydrous magnesium nitrate, Mg(NO3)2, will decompose into magnesium oxide and a mixture of gases shown in the following equation

      2Mg(NO3)2 (s) → 2MgO (s) + 4NO2 (g) + O2 (g)

      1.48 g of anhydrous magnesium nitrate is heated until no further reaction takes place.

      What mass of nitrogen dioxide is produced?

      • 0.92 g

      • 0.46 g

      • 1.48 g

      • 1.84 g

      Choose your answer

      41 mark

      A hydrocarbon, X, was burned in excess oxygen to give carbon dioxide and water as the only products. 0.1 mol of X produced 9.08 dm3 of carbon dioxide at standard conditions.

      What is the molecular formula of X?

      • CH4

      • C2H6

      • C3H8

      • C4H10

      Choose your answer

      51 mark

      A Group II metal of mass 0.33 g reacted with 154.0 cm3 of oxygen at 273 K and 100 kPa pressure, to form an oxide which contains O2– ions.

      What is the molar mass of the metal?

      • 0.02 g mol–1

      • 24.32 g mol–1

      • 17.38 g mol–1

      • 211.95 g mol–1

      Choose your answer

      61 mark

      Solid fertilisers are often rated by their NPK mass ratio. A particular fertiliser has a ratio of 20 g (N) : 30 g (P) : 10 g (K) per 100 g of fertiliser. It is recommended that 14 g of this fertiliser is used per 5 dm3 of water.

      What is the concentration of nitrogen, in mol dm-3, in the solution?

      • 0.02 mol dm-3

      • 0.03 mol dm-3

      • 0.04 mol dm-3

      • 0.05 mol dm-3

      Choose your answer

      71 mark

      When lead sulfide reacts with oxygen it produces lead(II) oxide and sulfur dioxide according to the equation below:

      PbS (s) + O2 (g) → PbO (s) + SO2 (g)

      What is the whole number sum of the coefficients in the balanced equation?

      • 4

      • 5

      • 8

      • 9

      Choose your answer

      81 mark

      Some coal contains as much as 3% sulfur.

      How much sulfur dioxide (Mr = 64.07 g mol-1) is produced by burning a lump of coal of mass 125 g?  (Ar S = 32.07)

      • 547.93 g

      • 7.49 g

      • 249.73 g

      • 1.88 g

      Choose your answer

      91 mark

      The conversion of toxic emissions into harmless products takes place in catalytic converters as follows:

      _CO (g) + _NO (g) → _CO2 (g) + _N2 (g)

      The sum of the coefficients is

      • 4

      • 5

      • 6

      • 7

      Choose your answer

      101 mark

      A compound is made of sulfur and oxygen only. A sample of the compound has a mass of 8.0 g and consists of 3.2 g of sulfur and 4.8 g of oxygen.

      What is the empirical formula?

      (Ar S = 32.07, O = 16.00)

      • SO

      • SO2

      • SO3

      • S2O3

      Choose your answer

      111 mark

      Which of the following samples has the largest mass?

      (Ar values: H = 1.01, N = 14.01, O = 16.00, S = 32.07)

      • 2.0 mol of NH4+

      • 1.0 mol of H2S

      • 1.0 mol of H2O2

      • 2.0 mol of OH-

      Choose your answer

      11 mark

      Natural gas contains on average 5.5 mg / m3 of hydrogen sulfide, H2S (Mr = 34.09).

      If a typical household in the UK consumes 0.198 m3 of gas per day, what is the average annual emission of sulfur in g per household?

      • 397.485 g

      • 0.423 g

      • 0.397 g

      • 0.374 g

      Choose your answer

      21 mark

      The coefficient for copper when the following equation is balanced is:

      _Cu   +  _HNO3   →  _Cu(NO3)2   + _NO   +   _H2O

      • 1

      • 2

      • 3

      • 4

      Choose your answer

      31 mark

      Excess dilute hydrochloric acid is added separately to equal masses of the four metals, calcium, zinc, magnesium and strontium.

      Which metal will give off the largest volume of hydrogen gas in the reaction?

      • calcium

      • zinc

      • magnesium

      • strontium

      Choose your answer

      41 mark

      When a 1.00 g sample of carbon is burned in a limited supply of oxygen, 0.72 g of the carbon combusts to form CO2 and the reaction also produces 0.28 g of CO.

      These gases were passed through excess NaOH (aq) which absorbs the CO2, but not the CO. The remaining gas was then dried and collected.

      Assuming that all gas volumes were taken at 273.15 K and 100 kPa pressure, what was the volume of gas at the end of the reaction? (Molar volume of a gas at STP = 22.7 dm3 mol-1)

      • 0.01 dm3

      • 100 cm3

      • 2.27 dm3

      • 227 cm3

      Choose your answer

      51 mark

      Chicken eggs are made up of 5.0% by mass of egg shell. The average egg has a mass of 50.0 g.

      Assume that chicken eggshell is pure calcium carbonate. 

      How many complete chicken’s egg shells would need to neutralise 50.0 cm3 of 2.00 mol dm-3 ethanoic acid?

      • 4

      • 3

      • 2

      • 1

      Choose your answer

      61 mark

      When a sample of potassium oxide, K2O, is dissolved in 250 cm3 of distilled water, 25 cm3 of this solution is titrated against sulfuric acid with a concentration of 2.00 mol dm-3. Complete neutralisation takes place with 15 cm3 of sulfuric acid.

      What is the mass of the original sample of potassium oxide dissolved in 250 cm3 of distilled water?

      • 14.13 g

      • 0.11 g

      • 28.26 g

      • 0.28 g

      Choose your answer

      71 mark

      Iron and chromium can be made into an alloy called ferrochrome. Ferrochrome can be dissolved in dilute sulfuric acid to produce FeSO4 and Cr2(SO4)3. The FeSO4 reacts with acidified K2Cr2O7 as shown in this equation:

      14H+ + 6Fe2+ + Cr2O72- → 2Cr3+ + 6Fe3+ + 7H2O

      When 1.00 g of ferrochrome is dissolved in dilute sulfuric acid and then titrated, 13.1 cm3 of 0.100 mol dm-3 K2Cr2O7 is needed for the complete reaction.

      In the sample of ferrochrome, what is the percentage by mass of Fe?

      • 43.90%

      • 0.44%

      • 7.32% 

      • 4.39 %

      Choose your answer

      81 mark

      Some fireworks can use the reaction between aluminium powder and anhydrous barium nitrate as a propellant. Metal oxides and nitrogen are the only products when this happens.

      10Al + 3Ba(NO3)2 → 5Al2O3 + 3BaO + 3N2

      When 0.783 g of anhydrous barium nitrate (Mr 261.35) reacts with an excess of aluminium what is the volume of nitrogen produced in cm3? (Molar volume of a gas at stp = 22.7 dm3)

      • 204.03 cm3

      • 7.58 cm3

      • 0.01 cm3

      • 68.01 cm3

      Choose your answer

      91 mark

      Excess acidified potassium dichromate(VI) was mixed with 2.76 g of ethanol. The reaction mixture was then boiled under reflux for one hour. Once the reaction had completed, the organic product was collected by distillation.

      The yield of the product was 75.0%

      What is the mass of the product collected?

      • 3.60 g

      • 2.70 g

      • 4.80 g

      • 1.59 g 

      Choose your answer

      101 mark

      The concentration of calcium ions in a sample of water can be determined by using an ion-exchange column, shown in the diagram below:

      1-2-h-q9-ib-chemistry-mcqs

       A 50 cm3 sample of water containing dissolved calcium sulfate was passed through the ion-exchange resin.

      Each calcium ion in the sample was exchanged for two hydrogen ions. The resulting acidic solution collected in the flask required 25 cm3 of 1.0 x 10-2 mol dm-3 potassium hydroxide for complete neutralisation.

      What was the concentration of the calcium sulfate in the original sample?

      • 0.01 mol dm–3

      • 5.0 x 10–3 mol dm–3

      • 2.5 mol dm–3

      • 2.5 x 10–3 mol dm–3

      Choose your answer