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`The movement of a substance very slowly from an area of high concentration to an area of low concentration.`
Which process is being described?
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When a dark grey solid element is heated, it changes directly into a purple gas. Which word describes this change?
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Nickel(II) sulfate is a green solid that is soluble in water. Which method is used to obtain a pure sample of nickel(II) sulfate crystals from a mixture of nickel(II) sulfate and sand?
566
555
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In the chromatography experiment shown, which label represents the solvent front?
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505
What is the meaning of the term nucleon number?
521
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The diagram represents the structure of a solid.
What could the solid be?
[Table_1: Showing options for brass, graphite, and sodium chloride]
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Magnesium reacts with sulfuric acid.
What are the formulae of the products formed in this reaction?
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Which diagram shows the arrangement of the outer shell electrons in a molecule of water?
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Rubidium is in Group I of the Periodic Table and bromine is in Group VII.
Rubidium reacts with bromine to form an ionic compound.
Which row shows the electron change taking place for rubidium and the correct formula of the rubidium ion?
[Table_1]
electron change | formula of ion formed
A | electron gained | $\text{Rb}^{+}$
B | electron gained | $\text{Rb}^{-}$
C | electron lost | $\text{Rb}^{+}$
D | electron lost | $\text{Rb}^{-}$
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Which statement explains why graphite is used as a lubricant?
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The relative atomic mass of chlorine is 35.5.
When calculating relative atomic mass, which particle is the mass of a chlorine atom compared to?
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Molten sodium chloride is electrolysed using inert electrodes.
Which row shows the products formed at the cathode and anode?
[Table_1]
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Ethanol is used as a fuel.
Ethanol + oxygen $\rightarrow$ carbon dioxide + water
Which statements are correct?
1. The reaction is endothermic.
2. The products have more energy than the reactants.
3. The oxygen for this reaction comes from the air.
4. The temperature of the reaction mixture rises during this reaction.
530
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Hydrogen and the isotope uranium-235 are both used to generate electricity. Which term describes the change that occurs for both substances in this context?
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Which substance does not require oxygen in order to produce energy?
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When calcium carbonate reacts with dilute hydrochloric acid, carbon dioxide gas is given off.
This causes the reaction mixture to lose mass.
Four separate experiments are performed.
The starting mass, and the mass after five minutes, are measured for each reaction mixture.
In which experiment is carbon dioxide produced at the greatest rate?
[Table_1]
533
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528
Silver oxide reacts with magnesium to make silver and magnesium oxide.
$\text{Ag}_2\text{O} + \text{Mg} \rightarrow 2\text{Ag} + \text{MgO}$
Which substance is oxidised in this reaction?
528
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When pink crystals of cobalt(II) chloride are heated, steam is given off and the colour of the solid changes to blue.
$$\text{CoCl}_2 \cdot 6\text{H}_2\text{O} \rightleftharpoons \text{CoCl}_2 + 6\text{H}_2\text{O}$$
What happens when water is added to the blue solid?
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Which oxide is used to neutralise acidic gases in a power station?
537
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Period 3 of the Periodic Table contains the elements sodium to argon.
Element Q is a non-metal from this period.
Which statement about Q is correct?
504
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Equal masses of a solid, X, are added in turn to an aqueous solution, Y. The pH of the solution is measured after each addition until the pH becomes 7. The readings are plotted as shown. What are X and Y?
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An aqueous cation reacts with aqueous sodium hydroxide to form a white precipitate.
The precipitate is insoluble in excess sodium hydroxide.
What is the aqueous cation?
574
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Vinegar has a pH of 3. Which statement about vinegar is correct?
550
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A student carries out an experiment to prepare pure magnesium sulfate crystals. The diagram shows the first stage of the preparation.
He adds magnesium carbonate until no more reacts.
Which process should he use for the next stage?
552
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Which statement about the halogens and their compounds is correct?
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Which compound contains a transition metal ion and a halide ion?
551
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A flammable gas needs to be removed from a tank at an industrial plant.
For safety reasons, an inert gas is used.
Which gas is suitable?
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A substance, X, has the following properties.
1 It has a high melting point.
2 It conducts electricity in the solid and liquid states.
3 It is malleable.
4 It has a high density.
What is X?
548
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A metal M is between sodium and magnesium in the reactivity series. Which reactions occur with M and its oxide? [Table_1]
568
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Mild steel and stainless steel are two alloys containing the element iron.
Which row identifies a use of each alloy?
[Table_1]
579
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Coke (carbon) and limestone are two raw materials used in the extraction of iron from hematite.
Which type of reaction occurs when each substance is heated during the process?
[Table_1]
523
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563
Oxides of nitrogen are given out from car exhausts. Which row best shows why oxides of nitrogen are unwanted in the atmosphere?
[Table_1]
590
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Two reactions, P and Q, produce carbon dioxide.
C₆H₁₂O₆ \overset{P}{\rightarrow} CO₂ \overset{Q}{\leftarrow} Na₂CO₃
Which types of reaction are P and Q?
598
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Which gas is used as a food preservative?
551
514
524
Which calcium compound does not neutralise an acid soil?
568
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531
Petroleum is separated into fractions by fractional distillation. Separation occurs in a fractionating column. Some properties of three of these fractions are shown.
[Table_1]
Which statement is correct?
551
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589
How many atoms are there in one molecule of ethanoic acid?
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The flow chart shows the preparation of ethanol and some important chemistry of ethanol.
What are X, Y and Z?
578
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Which substance is not a fraction obtained from the fractional distillation of petroleum?
529
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Some plastics are non-biodegradable. What is the meaning of the term non-biodegradable?
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