Pure Chemistry MCQ Revision

1) On adding 50 g of impure limestone, CaCO3 (Mr = 100), to excess hydrochloric acid, 6.0 dm3 of CO2 was evolved at room temperature and pressure.

What is the percentage purity of the limestone?

2) When crude oil is fractionally distilled, which list best describes the mixture of compounds collected at the bottom of the fractionating column?

3) In which equation does the metal oxide act as an acidic oxide?

4) Francium, Fr, is an element in the same group of the Periodic Table as lithium, sodium and potassium. Which statement about francium is likely to be correct?

5) The energy level diagram of a reaction is shown below.

Which arrow represents the overall enthalpy change of the reverse reaction?

6) Hydrogen gas reacts with chlorine gas to form hydrogen chloride gas.

H2(g) + Cl2(g) → 2HCl(g)

What is the final volume of the gas mixture when 20 dm3 of hydrogen is reacted with 30 dm3 of chlorine gas at 100 C?

7) An unknown solid Q has the following properties.

•When aqueous sodium hydroxide is added until in excess to the solution, no visible reaction is observed.

• When dilute acid is added to Q, effervescence of a colourless gas is observed.

• Q dissolves in water to form a colourless solution.

• Q is stable to heat.

What is Q likely to be?

8) Which compound has the lowest percentage by mass of nitrogen?

9) Which property of elements increases from left to right of Period 3 of the Periodic Table?

10) Which of the following is the process by which a polyester is broken down into its monomers?

11) Oxygen was prepared and collected using the apparatus as shown in the diagram below.

The first tube of gas collected was discarded as it was contaminated. Which contaminant was in the gas?

12) Which statement about the electrolysis of molten magnesium chloride is incorrect?

13) Which equations below represent redox reactions?

1. H+ + OH− → H2O

2. MnO4− + 8H+ + 5e− → Mn2+ + 4H2O

3. Cl2 + 2Br −→ Br2 + 2Cl −

14) The flowchart shows some reactions of a compound T.

What could compound T be?

15) A warship had its hull plated in copper to protect its wooden hull from rotting. However, after 2 years at sea, it was found that the iron parts of the warship in contact with the copper plates were more corroded than normal. What is the best explanation for this observation?

16) Aqueous hydrogen peroxide decomposes to form water and oxygen gas. Two experiments were carried out to measure the rate of production of oxygen from aqueous hydrogen peroxide.

17) A reaction takes place in two stages in the presence of a catalyst:

Which ion is the catalyst in the reaction?

18) CH4, H2O and HCl are covalent compounds.

Which atoms in these compounds do not use all their outer shell electrons in bonding?

19) Which diagram best represents the structure of calcium oxide?

20) Which of the following statements about isotopes is correct?

21) 50.0 cm3 of 0.10 mol/dm3 silver nitrate, AgNO3, is added to 150.0 cm3 of 0.05 mol/dm3 of sodium iodide, NaI, in a beaker.

After the reaction, solid silver iodide is present in the beaker. What else is present in the mixture?

22) How many of the following processes will lead to an increase in greenhouse gas emissions?

23) Which statement does not explain why the speed of the reaction between zinc and dilute sulfuric acid increases when the acid is warmed?

24) When a 10 cm3 sample of a gaseous hydrocarbon was completely burnt in 35 cm3 of oxygen, the total volume of the products formed was 50 cm3.

Which equation represents the combustion of the hydrocarbon?

25) Calcium nitrate crystals contain water of crystallisation. Its formula may be written as Ca(NO3)2●nH2O.

When a 7.00 g sample of hydrated calcium nitrate is heated to remove all water, 4.90 g of anhydrous calcium nitrate remains after heating.

What is the value of n?

26) An impure sample of calcium carbonate with a mass of 1.70 g was reacted with excess hydrochloric acid and 360 cm3 of carbon dioxide was collected at room temperature and pressure. What is the percentage purity of the calcium carbonate?

27) Ammonia and excess carbon dioxide can react to form urea and water in a reaction.

2NH3 + CO2 → CON2H4 + H2O

The percentage yield of this reaction is 80 %.

What is the mass of ammonia required for this reaction to obtain 60.0 g of urea?

[Mr: NH3, 17; CO2, 44; CON2H4, 60; H2O, 18]

28) Which statement explains why sodium chloride, NaCl, has a lower melting point than magnesium oxide, MgO?

29) During an electrolysis experiment, the same amount of charge deposited 32.5 g of zinc and 10.2 g of vanadium.

What was the charge on the vanadium ion?

30) The partial structure of a polymer is shown below.

31) Which of these Group 1 elements reacts most violently with water?

32) Heavy water is made up of 2 deuterium( Hydrogen atoms with mass number 2)  atoms and 1 oxygen atom.

Which properties are true about heavy water?

1 Its boiling point is higher than 100 °C.

2. It reacts with sodium to form sodium hydroxide and hydrogen gas.

3 It can act as a solvent for sodium chloride.

33) Which one of the following could be used to distinguish aqueous solutions of sodium chloride and sodium iodide?

34) In which chemical reaction does the named product have a higher relative molecular mass than the reactant?

35) Which statement is correct?

36) A student has five reagents.

• dilute hydrochloric acid

• dilute sulfuric acid

• dilute nitric acid

• solid calcium carbonate

• solid copper(II) carbonate

How many soluble salts can be prepared?

37) Which of the following statements about a homologous series is correct?

38) Which of the following hydrocarbons would produce the sootiest flame when burnt in air?

39) A paper chromatography experiment was carried out to determine the inks present in a mixture, and the results shown below were obtained.

Which statement about the results is incorrect?

40) A student investigated the diffusion of ammonia gas, NH3, and hydrogen chloride gas, HCl. Two sets of apparatus were set up as shown below at room temperature and pressure.

The damp red litmus paper in apparatus 1 changed colour after 30 seconds. How long does it take for the damp blue litmus paper to change colour in apparatus 2?