Pure Chemistry MCQ Revision

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

What are the reactants?

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

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

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?

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?

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

The flowchart shows some reactions of a compound T.

What could compound T be?

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?

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

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

Which three salts are all prepared by titration?

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

Which of the following statements about isotopes is correct?

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?

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.

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?

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?

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.

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?

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?

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?

Which statement is correct?

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?

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?

CH4, H2O and HCl are covalent compounds.

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

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?

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?

Which equations below represent redox reactions?

1. H+ + OH− → H2O

2. MnO4− + 8H+ + 5e− → Mn2+ + 4H2O

3. Cl2 + 2Br −→ Br2 + 2Cl −

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?

Which diagram best represents the structure of calcium oxide?

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?

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

The energy level diagram of a reaction is shown below.

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

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

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.

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

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

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

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