Pure Chemistry MCQ Revision

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?

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

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?

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

The partial structure of a polymer is shown below.

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

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.

Which equations below represent redox reactions?

1. H+ + OH− → H2O

2. MnO4− + 8H+ + 5e− → Mn2+ + 4H2O

3. Cl2 + 2Br −→ Br2 + 2Cl −

Which compound has the lowest percentage by mass of nitrogen?

An element T forms an ion, T2+, which has an electronic arrangement 2.8.8.

Which statement(s) concerning T is/are correct?

I T is an alkali metal.

II T forms a basic oxide with oxygen.

III T is in Period 4 of the Periodic Table.

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

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?

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?

The structure of brass is shown below.

What is the purpose of adding zinc to copper?

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?

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?

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

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

Which ion is the catalyst in the reaction?

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.

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

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?

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

When excess aluminium oxide, Al2O3 was added to a portion of dilute sodium hydroxide. Which of the following correctly describes the pH change and the explanation?

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?

The flowchart shows some reactions of a compound T.

What could compound T be?

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?

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

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

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?

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?

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?

Which statement is correct?

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

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

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?

Which three salts are all prepared by titration?

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?

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

What are the reactants?

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

CH4, H2O and HCl are covalent compounds.

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