O Level Chemistry 5070 Paper 11, May/June 2024

A scientist heats a sample of a liquid. The scientist measures the temperature of the sample and plots a graph of the temperature against time. Which statements are correct? 1 Between points W and X, the temperature increases and the particles move faster. 2 Between points X and Y, there is no change in the temperature because energy is needed to change a liquid into a gas. 3 Between points Y and Z, the particles move further apart. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 only

A sample of substance X contains iron and sulfur only. [$A_{\mathrm{r}}$: Fe, 56; S, 32] In which row is it possible for both statements about X to be correct?

A chlorine atom, Z, has a nucleon number of 37. Which row is correct?

Which particles are isotopes of the same element?

A W and X B W and Z C X and Z D Y and Z

Statements about graphite and silicon(IV) oxide, ${\mathrm{S}\mathrm{i}\mathrm{O}}_2$, are given. Which statement is correct? A Silicon(IV) oxide is found as an impurity in iron ore. B The angles between the atoms in silicon(IV) oxide and graphite are the same. C The melting points of silicon(IV) oxide and graphite are high because ionic bonds are stronger than covalent bonds. D When graphite acts as a lubricant, the covalent bonds between the layers are broken.

Statements about empirical and molecular formulae are given. Which statement is correct? A The empirical and molecular formulae of a compound are always different. B The empirical formulae of ethyne, ${\mathrm{C}}_2{\mathrm{H}}_2$, and of benzene, ${\mathrm{C}}_6{\mathrm{H}}_6$, are the same. C The molecular formula always shows the simplest whole-number ratio of the different atoms or ions in a compound. D The empirical formula always shows the numbers and types of different atoms in one molecule of a compound.

What is the relative formula mass, $M_{\mathrm{r}}$, of aluminium oxide? A 43 B 75 C 102 D 113

How many ions are there in $16.0\text{ g}$ of anhydrous copper sulfate? A $1.20\times {10}^{23}$ B $3.61\times {10}^{23}$ C $1.20\times {10}^{24}$ D $3.61\times {10}^{24}$

Which sample contains the most atoms? A $0.5\text{ mol}$ of water B $1.0\text{ mol}$ of carbon dioxide C $1.0\text{ mol}$ of methane D $2.0\text{ mol}$ of hydrogen chloride

The reactions shown all produce hydrogen. Which reaction produces the greatest volume of hydrogen, measured at room temperature and pressure? A $1.4\text{ g}$ carbon reacts with excess steam. $$\mathrm{C}(\mathrm{s})+{\mathrm{H}}_2\mathrm{O}(\mathrm{g})\to {\mathrm{H}}_2(\mathrm{g})+\mathrm{C}\mathrm{O}(\mathrm{g})$$ B $2.4\text{ g}$ calcium hydride, ${\mathrm{C}\mathrm{a}\mathrm{H}}_2$, reacts with excess water. $$\mathrm{C}\mathrm{a}{\mathrm{H}}_2(\mathrm{s})+2{\mathrm{H}}_2\mathrm{O}(\mathrm{l})\to \mathrm{C}\mathrm{a}(\mathrm{O}\mathrm{H}{)}_2(\mathrm{a}\mathrm{q})+2{\mathrm{H}}_2(\mathrm{g})$$ C $4.0\text{ g}$ calcium reacts with excess dilute hydrochloric acid. $$\mathrm{C}\mathrm{a}(\mathrm{s})+2\mathrm{H}\mathrm{C}\mathrm{l}(\mathrm{a}\mathrm{q})\to \mathrm{C}\mathrm{a}\mathrm{C}{\mathrm{l}}_2(\mathrm{a}\mathrm{q})+{\mathrm{H}}_2(\mathrm{g})$$ D $50{\text{ cm}}^3$ of $2.0\text{ mol}\mathrm{/}{\text{dm}}^3$ sulfuric acid reacts with excess zinc. $$\mathrm{Z}\mathrm{n}(\mathrm{s})+{\mathrm{H}}_2\mathrm{S}{\mathrm{O}}_4(\mathrm{a}\mathrm{q})\to \mathrm{Z}\mathrm{n}\mathrm{S}{\mathrm{O}}_4(\mathrm{a}\mathrm{q})+{\mathrm{H}}_2(\mathrm{g})$$

Four solutions of $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$ are made by dissolving solid $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$ in distilled water. Which method makes a solution with a concentration of $0.10\text{ mol}\mathrm{/}{\text{dm}}^3$? [$M_{\mathrm{r}}$: $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}$, 40] A $1.6\text{ g}$ of $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}(\mathrm{s})$ to make $400{\text{ cm}}^3$ of solution B $3.2\text{ g}$ of $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}(\mathrm{s})$ to make $250{\text{ cm}}^3$ of solution C $4.0\text{ g}$ of $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}(\mathrm{s})$ to make $100{\text{ cm}}^3$ of solution D $8.0\text{ g}$ of $\mathrm{N}\mathrm{a}\mathrm{O}\mathrm{H}(\mathrm{s})$ to make $500{\text{ cm}}^3$ of solution

Which row shows the substances that can be electrolysed?

The apparatus shown is set up to electroplate a steel key with copper. The key does not get coated with copper. Which change needs to be made to electroplate the key? A increase the concentration of the aqueous copper(II) sulfate B increase the electric current C replace the solution with dilute sulfuric acid D reverse the electrical connections

Ammonium nitrate dissolves in water. $$\mathrm{N}{\mathrm{H}}_4\mathrm{N}{\mathrm{O}}_3(\mathrm{s})\stackrel{{\mathrm{H}}_2\mathrm{O}}{\to }\mathrm{N}{\mathrm{H}}_4\mathrm{N}{\mathrm{O}}_3(\mathrm{a}\mathrm{q})\mathrm{\Delta }H=+25\text{ kJ}\mathrm{/}\text{mol}$$ Which statements are correct? 1 The process is endothermic. 2 The water gets colder during the process. 3 Thermal energy is absorbed by the ammonium nitrate from the water. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Hydrogen reacts with oxygen to produce water. $$\begin{array}{c}\mathrm{H}-\mathrm{H}\\ \mathrm{H}-\mathrm{H}\end{array}+\mathrm{O}=\mathrm{O}\to \begin{array}{c}\mathrm{H}-\mathrm{O}-\mathrm{H}\\ \mathrm{H}-\mathrm{O}-\mathrm{H}\end{array}$$ Some bond energies are shown.

Using the data in the table, what is the enthalpy change of reaction? A $-920\text{ kJ}\mathrm{/}\text{mol}$ B $-834\text{ kJ}\mathrm{/}\text{mol}$ C $-484\text{ kJ}\mathrm{/}\text{mol}$ D $+442\text{ kJ}\mathrm{/}\text{mol}$

Silicon(IV) chloride, ${\mathrm{S}\mathrm{i}\mathrm{C}\mathrm{l}}_4$, boils at $58{}^{\circ }\mathrm{C}$. Which row shows the type of change when silicon(IV) chloride boils and the explanation?

A $2\text{ g}$ sample of calcium carbonate reacts with dilute hydrochloric acid as shown. $$\mathrm{C}\mathrm{a}\mathrm{C}{\mathrm{O}}_3(\mathrm{s})+2\mathrm{H}\mathrm{C}\mathrm{l}(\mathrm{a}\mathrm{q})\to \mathrm{C}\mathrm{a}\mathrm{C}{\mathrm{l}}_2(\mathrm{a}\mathrm{q})+\mathrm{C}{\mathrm{O}}_2(\mathrm{g})+{\mathrm{H}}_2\mathrm{O}(\mathrm{l})$$ Which change in conditions makes the reaction proceed more slowly? A increasing the acid concentration B increasing the size of the solid particles C increasing the surface area of the solid particles D increasing the temperature

Excess aluminium reacts with dilute hydrochloric acid. $$2\mathrm{A}\mathrm{l}+6\mathrm{H}\mathrm{C}\mathrm{l}\to 3{\mathrm{H}}_2+2\mathrm{A}\mathrm{l}\mathrm{C}{\mathrm{l}}_3$$ The hydrogen given off is collected in a gas syringe. The total volume of hydrogen in the gas syringe is recorded every two minutes. The results of this experiment are shown.

Which statement is correct? A The mass of aluminium added is $0.107\text{ g}$. B The mass of aluminium added cannot be determined from the information given. C The highest rate of reaction is $71.5{\text{ cm}}^3\mathrm{/}\text{min}$. D The highest rate of reaction is when the acid concentration is highest.

$157.75\text{ g}$ of bismuth(III) chloride, ${\mathrm{B}\mathrm{i}\mathrm{C}\mathrm{l}}_3$, is used to make $500{\text{ cm}}^3$ of solution using distilled water. The aqueous bismuth(III) chloride slowly becomes cloudy as it reacts with water to form insoluble $\mathrm{B}\mathrm{i}\mathrm{O}\mathrm{C}\mathrm{l}$. The reaction is reversible. $$\mathrm{B}\mathrm{i}\mathrm{C}{\mathrm{l}}_3(\mathrm{a}\mathrm{q})+{\mathrm{H}}_2\mathrm{O}(\mathrm{l})\rightleftharpoons \mathrm{B}\mathrm{i}\mathrm{O}\mathrm{C}\mathrm{l}(\mathrm{s})+2\mathrm{H}\mathrm{C}\mathrm{l}(\mathrm{a}\mathrm{q})$$ Which statements are correct? 1 The initial concentration of the bismuth(III) chloride solution is $1.0\text{ mol}\mathrm{/}{\text{dm}}^3$. 2 At equilibrium, the rate of the forward reaction equals the rate of the reverse reaction. 3 When more hydrochloric acid is added, the position of equilibrium moves to the left. [$A_{\mathrm{r}}$: Bi, 209; Cl, 35.5] A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

The flow chart shows some of the processes and reactions in the formation of ammonia. What are the names of process X, substance 1 and substance 2?

Many reactions involve oxidation and reduction. Which statement is correct? A Acidified manganate(VII) ions change colour from colourless to purple when reduced. B All reactions that involve oxidation also involve reduction. C During a reaction, oxidising agents lose electrons. D Reduction is the loss of hydrogen from a compound.

The equation for a reaction is shown. $$\mathrm{C}{\mathrm{l}}_2+2\mathrm{K}\mathrm{B}\mathrm{r}\to 2\mathrm{K}\mathrm{C}\mathrm{l}+\mathrm{B}{\mathrm{r}}_2$$ Which statement about this reaction is correct? A Bromide ions are the oxidising agent. B Bromine is the reducing agent. C Chloride ions are the reducing agent. D Chlorine is the oxidising agent.

Which row describes both the pH and the ion with the greatest concentration in an aqueous alkali?

The water in a lake is acidic and the fish are dying. The water in the lake needs to be neutralised so that its pH is close to 7. Which compound is added in excess to neutralise the water in the lake? A calcium carbonate B phosphoric acid C potassium hydroxide D sodium nitrate

Which pair of reagents is used in a school laboratory to prepare a sample of pure barium sulfate? A barium carbonate and dilute sulfuric acid B barium carbonate and sodium sulfate C barium chloride and sodium sulfate D barium hydroxide and concentrated sulfuric acid

The total number of electrons in one atom of element Q is 17 and in one atom of element R is 19. Which statement about elements Q and R is correct? A Q and R react together to form a covalent compound. B Q forms positive ions. C R has more outer shell electrons than Q. D R is more metallic than Q.

Which statements about the Group VIII noble gases are correct? 1 They are unreactive. 2 They all have a full outer shell of electrons. 3 They are all diatomic gases at room temperature and pressure. A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

Iron has a high melting point. Which statement explains the high melting point of iron? A Each iron cation has a strong electrostatic attraction to a 'sea' of delocalised electrons. B In every iron atom there is a strong attraction between the protons and the electrons. C Iron has the same structure as diamond which has a very high melting point. D Iron is an alloy and alloys have different physical properties from the elements they contain.

Which statement about alloys is correct? A Alloys are not electrical or thermal conductors. B Alloys are softer than pure metals because the layers in the alloy slip over each other more easily. C Brass is a mixture of copper with small amounts of chromium, nickel and carbon. D The percentage of each metal in an alloy may vary.

The table shows the reactions of four metals, P, Q, R and S, and their oxides.

What is the order of reactivity, from the most reactive to the least reactive metal? A $\mathrm{P}>\mathrm{S}>\mathrm{Q}>\mathrm{R}$ B $\mathrm{P}>\mathrm{S}>\mathrm{R}>\mathrm{Q}$ C $\mathrm{S}>\mathrm{P}>\mathrm{Q}>\mathrm{R}$ D $\mathrm{S}>\mathrm{P}>\mathrm{R}>\mathrm{Q}$

Which reactions take place during the extraction of aluminium from aluminium oxide using carbon electrodes? 1 $2{\mathrm{O}}^{2-}\to {\mathrm{O}}_2+4{\mathrm{e}}^{-}$ 2 $\mathrm{C}+{\mathrm{O}}_2\to \mathrm{C}{\mathrm{O}}_2$ 3 ${\mathrm{A}\mathrm{l}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{A}\mathrm{l}$ A 1, 2 and 3 B 1 and 2 only C 1 only D 2 and 3 only

NPK fertilisers are used to improve plant growth. A solid NPK fertiliser has the properties listed: ● water soluble ● has an aqueous solution with pH 7. Which substances are mixed to make a solid NPK fertiliser? A ammonium nitrate, potassium sulfate and phosphorus oxide B ammonium phosphate and potassium hydroxide C ammonium sulfate, calcium nitrate and sodium phosphate D potassium nitrate and sodium phosphate

Alkanes are saturated compounds containing carbon and hydrogen only. Structures 1, 2, 3 and 4 are saturated hydrocarbons. Which pair of structures are isomers? A 1 and 2 B 1 and 4 C 2 and 3 D 2 and 4

Which statement is correct? A Any compound that contains both hydrogen and carbon is a hydrocarbon. B Petroleum is a compound formed from many different hydrocarbons. C The boiling points of hydrocarbons increase when the chain length increases. D The naphtha fraction obtained from petroleum is used for making roads.

Compound Q is a hydrocarbon that has no structural isomers. Compound Q does not decolourise bromine in the dark. Which compound is Q? A ${\mathrm{C}}_3{\mathrm{H}}_6$ B ${\mathrm{C}}_3{\mathrm{H}}_8$ C ${\mathrm{C}}_4{\mathrm{H}}_8$ D ${\mathrm{C}}_4{\mathrm{H}}_{10}$

Which equations represent the reactions of alkanes? 1 $\mathrm{C}{\mathrm{H}}_4+\mathrm{C}{\mathrm{l}}_2\to \mathrm{C}{\mathrm{H}}_2\mathrm{C}{\mathrm{l}}_2+{\mathrm{H}}_2$ 2 $2{\mathrm{C}}_2{\mathrm{H}}_6+5{\mathrm{O}}_2\to 4\mathrm{C}\mathrm{O}+6{\mathrm{H}}_2\mathrm{O}$ 3 ${\mathrm{C}}_3{\mathrm{H}}_8+\mathrm{H}\mathrm{C}\mathrm{l}\to {\mathrm{C}}_3{\mathrm{H}}_7\mathrm{C}\mathrm{l}+{\mathrm{H}}_2$ A 1 and 2 B 1 and 3 C 2 and 3 D 2 only

Ethanol is produced using either ethene or glucose as the starting material. Which row is correct?

The diagram shows four pieces of apparatus that are used to measure the volume of liquid. Which piece of apparatus is always filled to the same level? A B C D

The chromatogram shown is produced using a spot of black ink placed at point X. Spot M is produced by a blue dye in the ink. What is the $R_{\mathrm{f}}$ value of this blue dye? A 0.22 B 0.25 C 0.33 D 0.43

The table shows the results of a series of tests with two substances, X and Y.

Which row shows the identities of the ions present in X and Y?