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The particles in a substance are far apart, randomly arranged and moving.
The substance changes state and the particles are now close together. The particles are still randomly arranged and able to move.
What is the change of state of the substance?
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A student put exactly 25.00 cm$^3$ of dilute hydrochloric acid into a conical flask. The student added 2.5 g of solid sodium carbonate and measured the change in temperature of the mixture.
Which apparatus does the student need to use?
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A student separates sugar from pieces of broken glass by dissolving the sugar in water and filtering off the broken glass.
What is the filtrate?
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The nucleus of a particular atom consists of nineteen particles.
Nine of them are positively charged and ten of them are uncharged.
Which statement about this nucleus is correct?
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A Group I element combines with a Group VII element and forms an ionic bond. Which row shows how the electronic structures change?
[Table_1]
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Four covalent compounds are listed.
chlorine
methane
ammonia
water
Which row identifies the total number of covalent bonds in each compound?
[Table_1]
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Magnesium reacts with dilute hydrochloric acid to produce a salt and hydrogen gas. What is the equation for this reaction?
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The formula of sodium chlorate (V) is $\text{NaClO}_3$.
What is the relative formula mass of sodium chlorate (V), $\text{NaClO}_3$?
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Effervescence is observed at the negative electrode (cathode) during the electrolysis of concentrated aqueous sodium chloride. Which element is produced at the negative electrode (cathode)?
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The energy level diagram for a chemical reaction is shown.
Which statement about this reaction is correct?
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Which property explains why methane is used as a fuel?
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Solid copper(II) carbonate reacts with dilute sulfuric acid.
\[ \text{CuCO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{CuSO}_4 + \text{CO}_2 + \text{H}_2\text{O} \]
The rate of the reaction can be changed by varying the conditions.
Which changes always increase the rate of this chemical reaction?
1. increasing the concentration of sulfuric acid
2. increasing the size of the pieces of copper(II) carbonate
3. increasing the temperature
4. increasing the volume of sulfuric acid
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Magnesium carbonate and hydrochloric acid react to form a gas. The volume of gas is measured at fixed time intervals. In experiment 1, an excess of magnesium carbonate granules reacts with 100 cm${^3}$ of hydrochloric acid. The experiment is repeated but with one change. This is experiment 2. The results are shown on the graph. Which change is made?
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Which colour change is observed when water is added to anhydrous cobalt(II) chloride?
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The equation for the extraction of iron from its ore is shown.
$$ \text{Fe}_2\text{O}_3 + 3\text{CO} \rightarrow 2\text{Fe} + 3\text{CO}_2 $$
Which statement is correct?
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Solution X is tested separately with sodium carbonate and litmus.
Which row shows that X is acidic?
[Table_1]
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Basic oxides are neutralised by acidic oxides.
Which element forms an oxide that neutralises calcium oxide?
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Which method produces a pure sample of copper(II) sulfate crystals?
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Which statement about aqueous sodium hydroxide is correct?
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A period of the Periodic Table is shown.
[Table_1]
The letters are not their chemical symbols.
Which statement is correct?
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Lithium, sodium and potassium are elements in Group I of the Periodic Table. Which statement about sodium is correct?
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Which property of transition elements is different from the properties of Group I metals?
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The noble gases are in Group VIII of the Periodic Table. Which statement explains why noble gases are unreactive?
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Which statement is correct for all metals?
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Chromium is a more reactive metal than iron but less reactive than zinc.
Which statements are correct?
1 Chromium does not react with dilute hydrochloric acid.
2 Chromium oxide is reduced when it is heated with carbon.
3 Chromium reacts with zinc oxide to form zinc.
4 Chromium reacts with steam to form hydrogen gas.
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Some properties of copper are listed.
1. It conducts electricity.
2. It conducts heat.
3. It is ductile.
4. It has a high melting point.
Which properties of copper make it useful as a cooking pan?
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The diagrams show some uses of water in the home.
For which uses is it important for the water to have been treated?
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Which gas is released when slaked lime, $\text{Ca(OH)}_2$, is added to a field that has previously been treated with ammonium sulfate fertiliser?
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Which reactions produce carbon dioxide?
1. heating a carbonate
2. reacting a carbonate with dilute acid
3. burning methane
4. cracking a hydrocarbon
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Sulfur burns to make sulfur dioxide.
Which row describes a source of sulfur and a use of sulfur dioxide?
[Table_1]
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Lime (calcium oxide) is used to treat waste water from a factory.
Which substance is removed by the lime?
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The structures of three chemical compounds are shown.
To which homologous series do 1, 2 and 3 belong?
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Fuel X produces carbon dioxide and water when it is burned in air. So does fuel Y.
What could X and Y be?
[Table_1]
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What is the main constituent of natural gas?
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Which statement describes the members of a homologous series?
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Which monomer molecules are used to make poly(ethene)?
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Ethanol is manufactured by the catalytic addition of steam to compound P.
What is P?
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Which property is shown by aqueous ethanoic acid?
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