Sec 4 Pure Chem TYS MCQ 2019 set B
Quiz by HAO YI
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A gas turns moist red litmus paper blue, is soluble in water and is less dense than air.
Which diagram shows a correct way of drying and collecting the gas?
In addition to sodium ions and chloride ions, sea water contains calcium ions and sulfate ions.
Which method could be used to measure the amount of sulfate ions present in a sample of sea water?
Liquids X and Y are immiscible.
- X has a higher boiling point than Y.
- X has a higher density than Y.
- X and Y can be separated from each other both by fractional distillation and by use of a separating funnel.
Which row correctly gives the first liquid to be collected by fractional distillation and the lower liquid in the separating funnel?

These different experiments with colour changes are carried out.
1 Sulfur dioxide is tested with acidified potassium manganate(VII) solution.
2 Universal indicator solution is added to a solution of a weak acid.
3 Aqueous potassium iodide and dilute nitric acid are mixed. Then aqueous silver nitrate is added.
Which row correctly identifies the experiments that correspond to the colour changes?

Which property is common to both diamond and graphite?
Both calcium chloride and potassium chloride are ionic compounds.
Which statements about these compounds are correct?
1 Potassium chloride has a higher melting point than calcium chloride because the potassium ion has a greater charge than the calcium ion.
2 In the calcium chloride lattice, the ratio of calcium ions to chloride ions is half that of the ratio of potassium ions to chloride ions in the potassium chloride lattice.
3 Molten calcium chloride has a greater electrical conductivity than molten potassium chloride because calcium contributes more electrons to the delocalised 'sea of electrons' than does potassium.
Statements about two substances X and Y are given.
X is a gas at room temperature and pressure that burns to produce carbon dioxide and water.
Y is a macromolcule that has small units joined by amide linkages.
What are X and Y?

For which does 1 moles of the metal have the most electrons in its 'sea of electrons'?
A carbohydrate has the formula (CH2O)6.
One mole of this carbohydrate is burned in excess oxygen and the gas formed is collected.
What volume of gas, measured at room temperature and pressure, is collected?

4.00 g of a metal oxide, XO2, is reduced to form 3.15 g of metal X.
What is the identity of X?
Four different conditions under which sodium chloride is electrolysed using inert electrodes are listed.
1 concentrated aqueous sodium chloride
2 dilute aqueous sodium chloride
3 molten sodium chloride
4 solid sodium chloride
Under which conditions is a green gas formed?
Aqueous copper(II) sulfate is electrolysed using a positive carbon electrode and a negative copper electrode.
Which row is correct?

The energy profile diagram for the reversible reaction 2NH3 ⇌ N2 + 3H2 is shown.
Which statements about this reaction are both correct?

The table shows information about some fuels.
Which statements are correct?
1 Octane produces more heat than hydrogen or methane for each gram of fuel burned.
2 On complete combustion, 1 g of hydrogen produces 286 kJ of energy.
3 When methane is completely combusted, the energy required for bond breaking is less than the energy released in bond forming.

Dilute hydrochloric acid is reacted with 1.2 g of magnesium ribbon at room temperature in two experiments, experiment 1 and experiment 2.
In experiment 1, 100 cm3 of 1 mol/dm3 hydrochloric acid is used.
In experiment 2, 50 cm3 of 2 mol/dm3 hydrochloric acid is used.
The volume of hydrogen given off is plotted against time.
Which graph is correct?
How is the activation energy for a reaction between two gases changed when it is carried out either in the presence of a catalyst or when the temperature is increased?

In which reaction is substance X reduced?
An aqueous solution of sodium hydroxide has a pH of 10.
Which compounds could be added to the aqueous sodium hydroxide to decrease the pH?
1 sulfur dioxide
2 carbon dioxide
3 calcium oxide
Y is a white solid mixture that has the following properties.
Y dissolves in water.
When dilute hydrochloric acid is added to an aqueous solution of Y, bubbles are produced.
When chlorine is bubbled through an aqueous solution of Y the solution turns red-brown.
What is present in Y?
The diagram shows two substances, R and S, being heated together.
Which row is correct?

The oxygen in air can be removed by passing air over heated copper using the apparatus in the diagram.
50 cm3 of air is collected in gas syringe 1. Each syringe, 1 and 2, is pushed alternately so that the air passes repeatedly over the heated copper.
When the volume of gas no longer changes, and the gas has cooled to room temperature, what volume of gas will remain?

Element Z forms a positive ion when it reacts with oxygen.
Which statement about Z is correct?
Lithium reacts with water to form solution P and gas Q. When solution P reacts with dilute sulfuric acid, salt R is formed.
What are the formulae of P, Q and R?

Vanadium has various oxidation states and forms coloured compounds.
The aqueous VO2+ ion is blue while the aqueous VO2+ ion is yellow.
The aqueous V3+ ion is blue-green and the aqueous V2+ ion is violet in colour.
Which statement is correct?
Five statements about different elements are given.
1 proton number = 24
2 cuts easily with a knife
3 constituent of brass
4 burns in oxygen with a bright white light
Which statement is correct for each element?

Some of the reaction of three metals, W, X and Y, or compounds of these metals, are described.
The oxide of W is reduced both by heating with carbon and by heating with hydrogen.
The oxide of X is not reduced by heating with carbon or by heating with hydrogen.
W displaces Y from an aqueous solution of the sulfate of Y.
What is the order of reactivity of metals W, X and Y?

Metal M can be obtained from its oxide by heating with carbon and from its aqueous chloride by electrolysis.
Which metal is M?
Which pair of gases are involved in the formation of acid rain?
Petroleum can be separated into fractions using fractional distillation.
Which statements are correct?
1 Alkanes used in polishes and waxes have a higher boiling point than those used as diesel fuel.
2 Any of the fractions could be used as fuels because their enthalpy changes of combustion are negative.
3 The fraction used for petrol (gasoline) is extracted from higher up the fractionating column than the fraction used for paraffin (kerosene).
4 The fraction obtained at a particular point in the fractionating column always contains the same compounds in the same ratio.
Which diagram represent the two isomers of butane, C4H10?


What is added to polyunsaturated vegetable oils to form solid margarine?
Two of the isomers of butene, C4H8, are shown.
CH2=CHC2H5 and CH3CH=CHCH3
How many of the statements about these two isomers are correct?
- Both decolourise bromine water.
- Both produce the same molecule when reacted with bromine.
- Both produce the same molecule when reacted with hydrogen.
- When polymerised, the same polymer is produced.
Which statements about ethanol are correct?
Ethanol can be used:
1 as the source of energy in car engines
2 to dissolve the active ingredients in perfumes
3 to manufacture polyesters.
Which bond in a molecule of ethanoic acid is broken when it reacts with magnesium?
Which alcohol and acid can be reacted together to make the ester CH3CH2CH2CO2CH3?
The diagram shows the partial structure of a polymer.
Which statement about this polymer is correct?
