O Level Chemistry 5070 Paper 11, Oct/Nov 2024

Which row shows both a property of a gas and the correct explanation for this property?

When measured under the same conditions of temperature and pressure, which gas diffuses at the same rate as nitrogen? A ammonia, ${\text{NH}}_3$ B carbon monoxide, $\text{CO}$ C ethane, ${\text{C}}_2{\text{H}}_6$ D oxygen, ${\text{O}}_2$

X and Y are both elements, one of which is a non-metal. 1 mole of X is added to 1 mole of Y and they are heated together. X and Y react completely to form substance Z. Substance Z cannot be easily separated to form X and Y. Three statements are given. 1 Y must be the non-metal. 2 X and Y formed a compound on heating. 3 Substance Z has the empirical formula XY. Which statements are correct? A 1 and 3 B 1 only C 2 and 3 D 2 only

An ion has an electronic configuration of 2,8,8. It has a 2– charge and a nucleon number of 36. How many neutrons are present in the nucleus of this ion? A 16 B 18 C 19 D 20

The formulae for two ions are given. $${}_{34}^{72}{\text{X}}^{2-}{}_{34}^{74}{\text{X}}^{2-}$$ Which statement is correct? A The chemical properties of both ions are the same. B The number of electrons in each ion is different. C The number of neutrons in each ion is the same. D The number of protons in each ion is different.

Which pair of molecules have the same number of electrons in covalent bonds? A ${\text{CH}}_3\text{OH}$ and ${\text{C}}_2{\text{H}}_4$ B ${\text{CO}}_2$ and ${\text{H}}_2\text{O}$ C ${\text{NH}}_3$ and ${\text{N}}_2$ D ${\text{O}}_2$ and ${\text{Cl}}_2$

Chrome alum is a salt that contains two different cations and one anion. The ions present in chrome alum are ${\text{K}}^{+}$, ${\text{Cr}}^{3+}$ and ${\text{SO}}_4^{2-}$. What is the formula of the salt? A ${\text{KCrSO}}_4$ B $\text{KCr}({\text{SO}}_4{)}_2$ C $\text{KCr}({\text{SO}}_4{)}_3$ D ${\text{K}}_2\text{Cr}({\text{SO}}_4{)}_3$

The table gives some information about barium and chlorine.

Using this information only, a student makes three statements. 1 There is more than one isotope of chlorine. 2 There may be more than one isotope of barium. 3 The relative formula mass of barium chloride is 208. Which statements are correct? A 1, 2 and 3 B 1 and 3 only C 2 and 3 only D 3 only

Which mass of carbon contains the same number of atoms as $16.0\text{ g}$ of sulfur? A $0.5\text{ g}$ B $6.0\text{ g}$ C $8.0\text{ g}$ D $12.0\text{ g}$

Compound X contains carbon, hydrogen and oxygen only. It has an $M_r$ of 90. $100\text{ g}$ of compound X contains $40.0\text{ g}$ of carbon and $6.7\text{ g}$ of hydrogen. How many oxygen atoms are there in each molecule of compound X? A 1 B 2 C 3 D 4

Aqueous copper(II) sulfate is electrolysed using copper electrodes. Which row describes the changes that take place during the electrolysis?

Which row describes one advantage and one disadvantage of using a hydrogen-oxygen fuel cell to power a road vehicle?

Which statement about exothermic and endothermic reactions is correct? A In an endothermic reaction, energy is used to break bonds but no energy is released when bonds form. B In an endothermic reaction, energy is released when bonds form but more energy is used to break bonds. C In an exothermic reaction, energy is released both by breaking and by forming bonds. D In an exothermic reaction, energy is released when bonds form but no energy is needed to break bonds.

Two gases react together to produce a single product. The rate of the reaction is affected by an increase in pressure. The reaction is catalysed by platinum. Which row describes one effect on this reaction of increasing pressure and one effect on this reaction of adding platinum?

Calcium carbonate reacts with excess dilute hydrochloric acid to form carbon dioxide. The reaction is investigated in two experiments. The rate of the reactions is compared by measuring the volume of carbon dioxide formed over time in each experiment. The two rates are compared by plotting graphs. Which statement about experiments 1 and 2 is correct? A Experiments 1 and 2 both slow down as the reaction proceeds. B Experiments 1 and 2 must both use acid of the same concentration. C Experiments 1 and 2 must have been done at the same temperature. D Experiment 2 uses larger lumps of calcium carbonate. All other conditions stay the same.

If calcium carbonate is heated in a closed container, it will decompose, forming calcium oxide and carbon dioxide. Calcium oxide and carbon dioxide can recombine to form calcium carbonate. After some time, a position is reached where calcium carbonate is decomposing, and calcium oxide and carbon dioxide are recombining at the same rate. What is this position called? A activation energy B backward reaction C equilibrium D neutralisation

Which set of conditions is used in the Contact process?

Copper forms a red oxide, ${\text{Cu}}_2\text{O}$, and a black oxide, $\text{CuO}$. In the presence of a catalyst, aqueous hydrogen peroxide, ${\text{H}}_2{\text{O}}_2$, decomposes to form water. The black oxide has copper in a ......1...... oxidation state than in the red oxide. In forming water, hydrogen peroxide is ......2...... . Which words correctly complete gaps 1 and 2?

An organic compound, X, has a molecular formula ${\text{C}}_4{\text{H}}_8{\text{O}}_2$ and turns damp blue litmus paper red. What is the displayed formula of X?

Which statement about oxides is correct? A All acidic oxides are gases at room temperature. B All basic oxides dissolve in water to give alkalis. C Amphoteric oxides react with acids, alkalis and water. D Potassium oxide is a basic oxide.

A student is provided with suitable apparatus, distilled water and the following reagents. $$\text{solid magnesium hydroxide}\text{solid lead carbonate}$$ $$\text{dilute nitric acid}\text{aqueous sodium chloride}\text{aqueous sodium sulfate}$$ Which salts can the student prepare as a pure dry sample? A lead nitrate, magnesium nitrate, lead chloride, lead sulfate and magnesium sulfate B lead nitrate, magnesium nitrate, lead chloride and lead sulfate only C lead nitrate, magnesium nitrate and lead chloride only D lead nitrate and magnesium nitrate only

When heated, copper(II) sulfate crystals, ${\text{CuSO}}_4\cdot 5{\text{H}}_2\text{O}$, react as shown. $${\text{CuSO}}_4\cdot 5{\text{H}}_2\text{O}(\text{s})\to {\text{CuSO}}_4(\text{s})+5{\text{H}}_2\text{O}(\text{g})$$ When ......1...... copper(II) sulfate, which is ......2...... in appearance, is heated, it forms ......3...... copper(II) sulfate, which is ......4...... in appearance. Which words correctly complete gaps 1, 2, 3 and 4?

Which formula represents the oxide of element Z in Group II of the Periodic Table? A $\text{ZO}$ B ${\text{Z}}_2{\text{O}}_2$ C ${\text{ZO}}_3$ D ${\text{Z}}_2\text{O}$

Element X is in Group I. Some statements about element X are given. ● X is not the least dense element in Group I. ● X is more reactive than potassium. ● X has an $A_r$ value less than 100. Which element is X? A lithium B sodium C rubidium D caesium

A student makes three statements about metals and non-metals. 1 All alloys contain at least one metal. 2 All metals are good thermal and electrical conductors. 3 All solid non-metals are malleable. Which statements are correct? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

Group I elements and transition elements are metals. Student X suggests that the Group I elements are above hydrogen in the reactivity series but that not all transition elements are above hydrogen. Student Y suggests that the densities of Group I elements are lower than those of the transition elements. Which students are correct? A both X and Y B X only C Y only D neither X nor Y

The equations for three reactions are given. 1 $2{\text{O}}^{2-}\to {\text{O}}_2+4{\text{e}}^{-}$ 2 $\text{C}+{\text{O}}_2\to {\text{CO}}_2$ 3 $\text{CaO}+{\text{SiO}}_2\to {\text{CaSiO}}_3$ These reactions take place in the extraction of metals. Which row is correct?

The domestic water supply is treated to make it safe to drink. Which row identifies the treatment and its effect?

Sodium phosphate, ${\text{Na}}_3{\text{PO}}_4$, and ammonium nitrate, ${\text{NH}}_4{\text{NO}}_3$, are both used as fertilisers. Which row shows the correct percentage by mass of the element in each compound that improves plant growth?

Three processes are shown. 1 the decomposition of vegetation 2 emissions from a car engine 3 photosynthesis Which row shows a gas produced in each process?

Which compound is not an alkane, alkene, alcohol or carboxylic acid?

Alkenes can be produced by the cracking of alkanes, such as decane, ${\text{C}}_{10}{\text{H}}_{22}$. Which equation shows the cracking of decane to produce two different alkenes and at least one other product? A ${\text{C}}_{10}{\text{H}}_{22}\to 2{\text{C}}_2{\text{H}}_4+{\text{C}}_3{\text{H}}_6+{\text{C}}_4{\text{H}}_{10}$ B ${\text{C}}_{10}{\text{H}}_{22}\to {\text{H}}_2+2{\text{C}}_2{\text{H}}_4+{\text{C}}_3{\text{H}}_6+{\text{C}}_5{\text{H}}_{10}$ C ${\text{C}}_{10}{\text{H}}_{22}\to 2{\text{C}}_3{\text{H}}_6+{\text{C}}_4{\text{H}}_{10}$ D ${\text{C}}_{10}{\text{H}}_{22}\to {\text{H}}_2+2{\text{C}}_2{\text{H}}_4+2{\text{C}}_3{\text{H}}_6$

Alkenes undergo addition reactions with bromine to form dibromoalkanes. Which statement is correct? A Ethene and bromine react to produce 1,1-dibromoethane. B Propene and bromine react to produce 1,3-dibromopropane. C But-2-ene and bromine react to produce 2,2-dibromobutane. D But-1-ene and bromine react to produce 1,2-dibromobutane.

How many moles of oxygen are required for the complete combustion of 2 moles of ethanol? A 3 B 4 C 6 D 7

Two reactions are shown. $$\text{reaction 1}{\text{CH}}_2\text{CH}={\text{CH}}_2\text{OH}+{\text{H}}_2\stackrel{\text{Ni}}{\to }\text{compound X}$$ $$\text{reaction 2}\text{compound X}\stackrel{\text{acidified }{\text{KMnO}}_4(\text{aq})}{\to }\text{compound Y}$$ Which row is correct?

A section of the structure of a protein is shown. How many amino acid monomer molecules have been used to make this section of the structure? A 2 B 3 C 4 D 5

Which piece of apparatus is used to measure exactly $27.3{\text{ cm}}^3$ of a liquid? A a burette B a condenser C a measuring cylinder D a volumetric pipette

A student titrates aqueous sodium hydroxide with $0.1\text{ mol}\mathrm{/}{\text{dm}}^3$ hydrochloric acid. The titration results are used to calculate the concentration of the aqueous sodium hydroxide. Which row is correct?

A mixture of four coloured dyes is analysed by chromatography. The result is shown. Which change allows the four coloured dyes to be seen separately? A Measure the $R_f$ values of the spots carefully. B Run the chromatogram for a longer time. C Run the chromatogram using a different solvent. D Use a locating agent.

An aqueous solution contains cations of metal X. A precipitate forms when a few drops of aqueous sodium hydroxide are added to the solution. The precipitate dissolves in excess aqueous sodium hydroxide. What is a possible identity of metal X?

key ✓ = yes ✗ = no