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The rate of diffusion of two gases, methane, CH₄, and ethene, C₂H₄, is measured using the apparatus shown.
Which gas diffuses faster and why?
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A sample of a dye is investigated by chromatography. A line is drawn across a piece of chromatography paper and a spot of the dye is placed on it.
The paper is placed in water.
Which row is correct?
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The paper chromatogram below was obtained from four different dyes.
Which dye has an $R_f$ value of 0.7?
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Which statements about isotopes of the same element are correct?
1. They are atoms which have the same chemical properties because they have the same number of electrons in their outer shell.
2. They are atoms which have the same number of electrons and neutrons but different numbers of protons.
3. They are atoms which have the same number of electrons and protons but different numbers of neutrons.
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The table shows the electronic structure of four atoms.
[Table_1]
atom | electronic structure
---- | -------------------
W | 2,8,1
X | 2,8,4
Y | 2,8,7
Z | 2,8,8
Which two atoms combine to form a covalent compound?
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Which statement describes the attractive forces between molecules (intermolecular forces)?
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The diagram represents the general structure of a solid Z. What is Z?
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A compound, X, contains 40.0% carbon, 6.7% hydrogen and 53.3% oxygen by mass.
The relative molecular mass, $M_r$, of X is 60.
What is the molecular formula of X?
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25 cm$^3$ of 0.1 mol/dm$^3$ hydrochloric acid exactly neutralise 20 cm$^3$ of aqueous sodium hydroxide.
The equation for this reaction is:
NaOH + HCl $\rightarrow$ NaCl + H$_2$O
What is the concentration of the sodium hydroxide solution?
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Which reactions could take place at the anode during electrolysis?
1. $4\text{OH}^-(aq) \rightarrow 2\text{H}_2\text{O}(l) + \text{O}_2(g) + 4e^-$
2. $2\text{Cl}^-(aq) \rightarrow \text{Cl}_2(g) + 2e^-$
3. $\text{Cu}^{2+}(aq) + 2e^- \rightarrow \text{Cu}(s)$
4. $2\text{H}^+(aq) + 2e^- \rightarrow \text{H}_2(g)$
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The diagram shows some properties that substances may have.
To which labelled part of the diagram does $^{235}U$ belong?
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The diagram shows a simple cell.
Which statement about the process occurring when the cell is in operation is correct?
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Hydrogen burns exothermically in oxygen. The equation for the reaction is:
$2H_2 + O_2 \rightarrow 2H_2O$
The table shows the bond energies involved.
[Table_1]
What is the energy given out during the reaction?
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A liquid X reacts with solid Y to form a gas. Which two diagrams show suitable methods for investigating the rate (speed) of the reaction?
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Which statements explain why increasing temperature increases the rate of a chemical reaction?
1. Heat makes the molecules move faster and collide more often.
2. Heat makes the molecules collide with more energy so they are more likely to react.
3. Increasing temperature lowers the activation energy for the reaction.
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Steam reacts with carbon in an endothermic reaction.
$$ \text{C(s) + H}_2\text{O(g)} \rightleftharpoons \text{CO(g) + H}_2\text{(g)} $$
Which conditions of temperature and pressure would give the largest yield of hydrogen?
[Table_1]
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Which equation represents a reduction reaction?
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Which statements are properties of an acid?
1. reacts with ammonium sulfate to form ammonia
2. turns red litmus blue
[Table_1]
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Which row describes whether an amphoteric oxide reacts with acids and bases?
[Table_1]
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Which substance reacts with dilute sulfuric acid to form a salt that can be removed from the resulting mixture by filtration?
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Where in the Periodic Table is the metallic character of the elements greatest?
[Table_1]
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Some properties of four elements, P, Q, R, and S, are shown in the table.
Two of these elements are in Group I of the Periodic Table and two are in Group VII.
[Table]
Which statement is correct?
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Which of the following could be a transition element?
[Table_1]
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Two statements about argon are given.
1 Argon has a full outer shell of electrons.
2 Argon is very reactive and is used in lamps.
Which is correct?
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A student investigated the reactions of four metals, R, S, T and U, with solutions of their salts.
The results are given in the table.
[Table_1]
What is the order of reactivity of the metals, most reactive first?
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Three students, X, Y and Z, were told that solid P reacts with dilute acids and also conducts electricity.
The table shows the students’ suggestions about the identity of P.
[Table_1]
Which of the students are correct?
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Which statement about the uses of metals is correct?
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Aluminium is manufactured by electrolysis of aluminium oxide.
The diagram shows the electrolysis cell.
Which statement about the process is not correct?
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The diagram shows an experiment to investigate how paint affects the rusting of iron. What happens to the water level in tubes P and Q?
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A new planet has been discovered and its atmosphere has been analysed. The table shows the composition of its atmosphere. [Table_1] Which gases are present in the atmosphere of the planet in a higher percentage than they are in the Earth's atmosphere?
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Many car exhaust systems contain a catalytic converter.
Which change does not occur in a catalytic converter?
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Ammonia is formed by a reversible reaction.
$N_2(g) + 3H_2(g) \rightleftharpoons 2NH_3(g)$
The forward reaction is exothermic.
Which changes in conditions would increase the yield of ammonia?
[Table_1]
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The equation for an exothermic reaction in the Contact process is shown:
$2SO_2(g) + O_2(g) \rightarrow 2SO_3(g)$
Which effects do increasing the temperature and using a catalyst have on the rate of formation of sulfur trioxide, SO$_3$?
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A farmer’s soil is very low in both nitrogen \(N\) and phosphorus \(P\).
Which fertiliser would improve the quality of this soil most effectively?
[Table_1]
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The diagram shows the separation of petroleum into fractions.
What could X, Y and Z represent?
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Which of the compounds shown are in the same homologous series?
1. $\text{CH}_3\text{OH}$
2. $\text{CH}_3\text{CH}_2\text{OH}$
3. $\text{CH}_3\text{COOH}$
4. $\text{CH}_3\text{CH}_2\text{CH}_2\text{OH}$
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Which compounds contain the same number of carbon, hydrogen and oxygen atoms?
[Table_1]
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What is an advantage of producing ethanol by fermentation of sugar compared to the catalytic addition of steam to ethene?
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The structure of a monomer is shown.
Which polymer can be made from this monomer?
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