MCQ-2: Summer 2021

Which row about a change of state is correct?

Gases are separated from liquid air by fractional distillation.
The boiling points of four gases are shown.
Which gas is both monoatomic and a liquid at –200^∘C?

Two different food colourings, X and Y, are tested using chromatography.
Three pure dyes, 1, 2 and 3, are also tested.
The chromatogram is shown.

Which statements are correct?

1. X and Y both contain two or more dyes.
2. Dyes 2 and 3 are present in both X and Y.
3. The R_f of dye 1 is 0.625.

Which statement about the atoms of all the isotopes of carbon is correct?

Which diagram represents the structure of silicon(IV) oxide?

Lithium and fluorine react to form lithium fluoride.
A student writes three statements about the reaction.

1. Lithium atoms lose an electron when they react.
2. Each fluoride ion has one more electron than a fluorine atom.
3. Lithium fluoride is a mixture of elements.

Which statements are correct?

How many electrons are used to form covalent bonds in a molecule of methanol, CH₃OH?

Magnesium oxide has a high melting point.
Carbon dioxide has a low melting point.
Which row identifies the attractive forces that are broken when these compounds are melted?

The ionic half-equation for the formation of oxygen during the electrolysis of aluminium oxide is shown.
xO^2– → O₂ + ye^–
What are the values of x and y?

A compound has the formula XF₂ and has a relative mass of 70.
What is element X?

The diagram shows a section of an overhead power cable.

Which statement explains why a particular substance is used?

During the electrolysis of dilute sulfuric acid, hydrogen is collected at the cathode.
What is the ionic half-equation for this reaction?

Which row describes an endothermic reaction?

	energy level diagram	energy transfer
A		energy is transferred from the surroundings to the reaction
B		energy is transferred from the surroundings to the reaction
C		energy is transferred from the reaction to the surroundings
D		energy is transferred from the reaction to the surroundings

The equation for the complete combustion of methane is shown.
CH₄(g) + 2O₂(g) → CO₂(g) + 2H₂O(g)
The bond energies are shown in the table.

What is the energy change for the reaction?

Hydrogen fuel cells can be used to power cars.
Which statements about a fuel cell are correct?

1. The balanced equation for the reaction is H₂ + O₂ → H₂O.
2. The fuel cell generates electricity.
3. In the fuel cell hydrogen is reduced.
4. The reactants are gases at room temperature.

The apparatus shown is used to measure the rate of a reaction.

Which equation represents a reaction where the rate can be measured using this apparatus?

P is a hydrated metal salt with a blue colour. When P is heated, water is given off, leaving solid Q.
R is a hydrated metal salt with a pink colour. When R is heated, water is given off, leaving solid S.
Which row gives the name of P and the colour of S?

Magnesium reacts with copper(II) oxide to give magnesium oxide and copper.
Which substance is the oxidising agent in this reaction?

Part of the Periodic Table is shown.
Which element forms an acidic oxide?

When aqueous sodium hydroxide is added to a solution of a metal ion, a grey-green precipitate forms, which dissolves in excess to form a dark green solution.
What is the identity of the metal ion?

Which statements about strong acids are correct?

1. They have a high concentration of OH^– ions.
2. They have a pH value of 1.
3. They completely ionise in water.
4. They turn red litmus blue.

Metal X reacts with non-metal Y to form an ionic compound with the formula X2Y.
Which statements are correct?

1. X is in Group I of the Periodic Table.
2. X is in Group II of the Periodic Table.
3. Y is in Group VI of the Periodic Table.
4. Y is in Group VII of the Periodic Table.

The table gives some properties of Group IV elements.

Which row describes the properties of silicon?

The metal beryllium does not react with cold water.
It reacts with hydrochloric acid but cannot be extracted from its ore by using carbon.
Where is beryllium placed in the reactivity series?

magnesium
A
zinc
B
iron
C
copper
D

Why is cryolite used in the extraction of aluminium from bauxite?

Which statements about the uses of metals are correct?

1. Iron is used to make aircraft because iron has a low density.
2. Copper is used to make electric cables because copper is a good conductor of electricity.
3. Aluminium is used to make brass because aluminium is strong and hard.
4. Iron is mixed with additives to make an alloy used in chemical plant.

Which row describes the reactions of magnesium hydroxide and magnesium oxide?

The properties of an element are listed.

• Its melting point is 3414^∘C.
• Some of its compounds are catalysts.
• It has variable oxidation states.

Where is the element found in the Periodic Table?

Petrol burns in a car engine to produce waste gases which leave through the car exhaust.
One of these waste gases is an oxide of nitrogen.
Which statement describes how this oxide of nitrogen is formed?

Which combination of chemical compounds can be used to produce the fertiliser shown?

Which process does not produce carbon dioxide?

Which substance is used as a bleach in the manufacture of paper?

What is an industrial use of calcium carbonate?

Propane reacts with chlorine.
Which row shows a condition required for this reaction and identifies the type of reaction?

The pie chart represents the composition of natural gas.
Which sector represents methane?

Which statement describes the reaction between ethene and steam?

The formula of a hydrocarbon is C_xH_y.
The equation for its complete combustion is shown.
C_xH_y + 8O₂ ⟶ 5CO₂ + 6H₂O
What are the values of x and y?

The formula of an ester is CH₃CH₂CH₂COOCH₂CH₂CH₃.
Which acid and alcohol react together to make the ester?

Molecule 1 undergoes a process to make molecule 2.

Which row describes the molecules and the process?

Which structure represents a protein?