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Which two gases will diffuse at the same rate, at the same temperature?
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A student is asked to measure the time taken for 0.4 g of magnesium carbonate to react completely with 25.0 cm$^3$ of dilute hydrochloric acid.
Which pieces of apparatus does the student need?
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A substance is separated using chromatography.
The chromatogram is shown.
Which statement is not correct?
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Which statement about an ionic compound is not correct?
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The numbers of protons, neutrons and electrons present in the atoms P, Q, R and S are shown.
[Table_1]
Which atoms are isotopes of the same element?
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Carbon has three isotopes, $^{12}\text{C}$, $^{13}\text{C}$ and $^{14}\text{C}$.
Why do all three isotopes have the same chemical properties?
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Silicon(IV) oxide is a covalently bonded compound. Which statements are correct?
1. Silicon atoms form four single bonds in silicon(IV) oxide.
2. Oxygen atoms form two double bonds in silicon(IV) oxide.
3. Silicon(IV) oxide has a high melting point.
4. Silicon(IV) oxide contains one silicon atom and four oxygen atoms.
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Which statement describes the structure of copper?
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Magnesium carbonate decomposes on heating to form magnesium oxide and carbon dioxide as shown.
$\text{MgCO}_3 \rightarrow \text{MgO} + \text{CO}_2$
How much magnesium carbonate is needed to make 5.0 g of magnesium oxide?
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90 g of glucose is dissolved in water.
The glucose solution is fermented.
$$ \text{C}_6\text{H}_{12}\text{O}_6 \rightarrow 2\text{CO}_2 + 2\text{C}_2\text{H}_5\text{OH} $$
glucose, $M_r = 180$
ethanol, $M_r = 46$
After the fermentation finishes, 6.8 g of ethanol is obtained from the solution.
What is the percentage yield of ethanol?
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The diagram shows a simple cell.
Which metal P produces the smallest voltage?
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What are the ionic half-equations for the electrode reactions during the electrolysis of concentrated aqueous sodium chloride? [Table_1]
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An energy level diagram for a reaction is shown.
Which statement and explanation about this reaction are correct?
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Which gases are used to generate electricity in a fuel cell?
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A sequence of changes involving sulfur is shown.
$\text{S(s)} \xrightarrow{\text{change 1}} \text{S(l)} \xrightarrow{\text{change 2}} \text{SO}_{2}\text{(g)}$
Which row describes the changes?
[Table_1]
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Magnesium reacts with dilute hydrochloric acid.
Which statement about the particles in the reaction is correct?
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Two molecules of nitrogen dioxide combine in a reversible reaction to form dinitrogen tetroxide.
The forward reaction is exothermic.
$$2\text{NO}_2(g) \rightleftharpoons \text{N}_2\text{O}_4(g)$$
Which changes in reaction conditions would both increase the amount of dinitrogen tetroxide at equilibrium?
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Chlorine displaces bromine from aqueous potassium bromide. The ionic equation for the reaction is shown.
$\text{Cl}_2 + 2\text{Br}^- \rightarrow 2\text{Cl}^- + \text{Br}_2$
Which statement about this reaction is correct?
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Which statements about dilute sulfuric acid are correct?
1. It turns red litmus paper blue.
2. It reacts with magnesium(II) oxide to form magnesium(II) sulfate and water.
3. It reacts with magnesium to form magnesium(II) sulfate and carbon dioxide.
4. Its pH is below pH 7.
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A method used to make copper(II) sulfate crystals is shown.
1 Place dilute sulfuric acid in a beaker.
2 Warm the acid.
3 Add copper(II) oxide until it is in excess.
4 Filter the mixture.
5 Evaporate the filtrate until crystals start to form.
6 Leave the filtrate to cool.
What are the purposes of step 3 and step 4?
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Lead(II) iodide is formed as a precipitate in the reaction shown.
$$\text{Pb(NO}_3)_2(\text{aq}) + 2\text{NaI(}\text{aq}) \rightarrow \text{PbI}_2(\text{s}) + 2\text{NaNO}_3(\text{aq})$$
Which method is used to separate the lead(II) iodide from the mixture?
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Which statement describes a gas which is in Group VIII of the Periodic Table?
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Which pair of elements reacts together most violently?
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Iron reacts with dilute hydrochloric acid to form iron(II) chloride, $FeCl_2$. Iron reacts with chlorine to form iron(III) chloride, $FeCl_3$.
Which property of transition elements is shown by this information?
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Some properties of substance X are listed.
• It conducts electricity when molten.
• It has a high melting point.
• It burns in oxygen and the oxide dissolves in water to give a solution with pH 11.
What is X?
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Which statement about metals and their uses is correct?
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Which word equation represents a reaction which occurs?
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Why is cryolite used in the extraction of aluminium by electrolysis?
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River water contains soluble impurities, insoluble impurities and bacteria.
River water is made safe to drink by filtration and chlorination.
Which statement is correct?
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How are oxygen and nitrogen separated from air?
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The apparatus shown is set up and left for a week.
Which diagram shows the level of the water at the end of the week?
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The following processes are part of the carbon cycle.
1 photosynthesis
2 combustion
3 respiration
Which processes decrease the amount of carbon dioxide in the atmosphere?
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Ammonium sulfate is used as a fertiliser. It is made from ammonia and sulfuric acid. Which words complete gaps 1, 2 and 3?
The ......1...... is made by the ......2...... process in which ......3...... is used as a catalyst.
[Table_1]
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Which type of reaction occurs when lime is manufactured from limestone?
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Which products are obtained by the cracking of an alkane? [Table_1]
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Ethanol is made by fermentation of sugars and by the catalytic addition of steam to ethene.
What are two advantages of making ethanol by the catalytic addition of steam to ethene rather than by fermentation of sugars?
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The diagram shows the structure of a monomer and of the polymer made from it.
What are the monomer and polymer?
[Table_1]
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Proteins and starch are both natural polymers. Both proteins and starch are hydrolysed by dilute acids. What are the products of hydrolysis of proteins and of starch? [Table_1]
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