Pure Chemistry MCQ Revision

1) 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?

2) A solution of a lithium halide and a halogen are mixed. A reaction occurs and the mixture darkens in colour.

What are the reactants?

3) 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.

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

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

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

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

7) 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?

8) 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?

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

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

11) Which statement is correct?

12) 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.

13) The diagram shows the apparatus used to separate hexane (boiling point, 70 oC) and heptane (boiling point, 98 oC).

14) Three elements W, X, Y, and Z have consecutive, increasing proton (atomic) numbers. Element Y exists as a colourless, monatomic gas at room temperature.

Which will be the chemical formula of a compound formed between W and chlorine?

15) 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?

16) The following chemicals are available in the laboratory.

1. aqueous bromine
2. Universal Indicator solution
3. magnesium powder
4. sodium carbonate

Which of these chemicals can be used to distinguish between propene and propanoic acid?

17) 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?

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

19) Elements X, Y and Z are in the same period of the Periodic Table. Gaseous X exists as diatomic molecules.

Oxides of Y react with both acid and alkali.

Oxides of Z dissolve in water to form solution with pH > 7.

In which order do the elements appear in the Periodic Table?

20) Elements X and Y combine to form an ionic compound. Atoms of X have more protons than atoms of Y.

Atoms of Y have more valence electrons than atoms of X. Which statement is correct?

21) The structure of a compound associated with the smell of raspberries is shown below.

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

23) 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?

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

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

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

27) An unknown substance X starts melting at –180 °C and finishes melting at –160 °C. What is substance X likely to be?

28) 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?

29) 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?

30) Which element does not form a stable ion with the same electronic configuration as neon?

31) Which substances contain the same number of atoms?

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

33) 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]

34) CH4, H2O and HCl are covalent compounds.

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

35) Lead(IV) chloride has a melting point of -15 °C and boiling point of 50 °C.

Which type of structure do you expect lead(IV) chloride to have?

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

37) 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?

38) 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?

39) Water is formed when oxygen combines with hydrogen. What mass of oxygen combines with 6 g of hydrogen?

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