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Four physical changes of ethanol are listed.
1. condensation
2. evaporation
3. freezing
4. boiling
In which changes do the particles move further apart?
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An atom of element X contains: \begin{itemize} \item 5 protons \item 6 neutrons \item 5 electrons \end{itemize} Which statements about element X are correct? \begin{enumerate} \item X has an atomic number of 6. \item X has a nucleon number of 11. \item X is in Group II of the Periodic Table. \item X is in the second period of the Periodic Table. \end{enumerate}
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Ammonia, NH$_3$, is a covalent molecule. Which diagram shows the outer-shell electron arrangement in a molecule of ammonia?
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Which structure does silicon(IV) oxide most closely resemble?
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Substance P conducts electricity when solid. Which particles move in solid P so that it can conduct electricity? 1. anions 2. cations 3. electrons
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Which equation represents a chemical change?
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Which sample contains the largest number of molecules?
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The concentration of a sample of dilute aqueous sodium hydroxide is found by titration.
The apparatus used is shown.
Which information is needed to calculate the concentration of the dilute aqueous sodium hydroxide in mol/dm\(^3\)?
[Table_1]
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In experiment 1, aqueous copper(II) sulfate is electrolysed using graphite electrodes. In experiment 2, aqueous copper(II) sulfate is electrolysed using copper electrodes. Which statement identifies a half-equation for a reaction at one of the electrodes?
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Which substance is not produced during the electrolysis of concentrated aqueous sodium chloride?
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Methane burns in excess oxygen. The equation is shown.\ CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(g) \ Bond energies are shown.\ [Table_1]\ Bond energy in kJ/mol: C=O: 805, C–H: 410, O=O: 496, O–H: 460\ What is the energy change for the reaction?
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Which change increases the rate of reaction by decreasing the activation energy, $E_a$?
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In the Contact process, sulfur dioxide is reacted with oxygen to form sulfur trioxide. Which conditions are used in this reaction? [Table_1]
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Which reaction is reversible?
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The equation for the reaction of sulfur dioxide with acidified potassium dichromate(VI) is shown. $$3SO_2 + Cr_2O_7^{2-} + 2H^+ \rightarrow 3SO_4^{2-} + 2Cr^{3+} + H_2O$$ What is oxidised and what is the oxidising agent?
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What is the definition of a strong acid?
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Which statement about amphoteric oxides is correct?
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Copper(II) carbonate is formed when aqueous sodium carbonate is added to aqueous copper(II) nitrate. The ionic equation for the reaction is shown. $$\text{CO}_3^{2-} (aq) + \text{Cu}^{2+} (aq) \rightarrow \text{CuCO}_3 (s)$$ How is pure copper(II) carbonate obtained from the reaction mixture?
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Q and R are elements in the same period of the Periodic Table. Q has 7 electrons in its outer shell and R has 2 electrons in its outer shell. Which statement about Q and R is correct?
550
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Lead(II) sulfate is an insoluble salt.
Which reaction produces a mixture from which lead(II) sulfate is obtained by filtration?
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Which statement about alkali metals is correct?
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Which row describes the properties of a transition element? [Table_1]
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Which row identifies the properties of zinc? [Table_1]
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Uses of metals depend on their properties. Which property is necessary for the use given? | | use of the metal | property of the metal | |---|-------------------------------|------------------------| | A | car bodies | ductile | | B | cutlery | conducts heat | | C | food containers | resists corrosion | | D | overhead electrical cables | high density |
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Which compounds \textbf{both} contribute to acid rain?
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P, Q, R and S are metals.
P reacts with dilute hydrochloric acid, forming hydrogen.
Q reacts violently with water.
R reacts with water to give hydrogen.
S is formed by heating its oxide with carbon.
Which row identifies the metals?
[Table_1]
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Which compound is formed when iron rusts?
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Why is cryolite used in the extraction of aluminium by electrolysis?
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A wax candle is made from a mixture of hydrocarbons.
The candle is lit and placed in a gas jar along with a strip of cobalt(II) chloride test paper as shown.
After a short time, the oxygen in the jar is used up and the candle flame goes out.
Which substance does the cobalt(II) chloride paper identify?
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The hydrocarbon $C_4H_8$ has two structural isomers, but-1-ene and but-2-ene. Which statement is correct?
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Which compound rapidly decolourises aqueous bromine?
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What are the products of the addition reactions of ethene with bromine and hydrogen? [Table_1]
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Ethanol is manufactured by fermentation and the catalytic addition of steam to ethene.
Which row describes an advantage of both methods?
[Table_1]
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Methanoic acid and propan-1-ol react to form an ester. What is the structural formula of the ester?
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What is the correct structure of PET?
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Alkanes undergo substitution reactions in the presence of UV light. Which equation represents a substitution reaction of ethane?
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Methane reacts with chlorine in substitution reactions. How many different products, containing a single carbon atom, can be made during the reactions?
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Rock salt is a mixture of salt and sand. The method used to separate the sand from the salt is listed. step 1 Crush the rock salt, add to warm water and stir. step 2 Pour the mixture through a filter paper held in a funnel. step 3 Evaporate the water to crystallise the salt. Which statement about the method is correct?
578
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Two compounds, M and N, are dissolved in water and separated by chromatography. The results are shown. What is the $R_f$ value of M and which compound is most soluble in water?
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When acid is added to salt X, a gas is produced which turns limewater milky. When sodium hydroxide is added to salt X, a gas is produced which turns litmus paper blue. What is X?
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