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Diagrams R, S and T represent the three states of matter.
Which change occurs during freezing?
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A student needs to measure 22 cm$^3$ of water at 40°C. Which apparatus is required?
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A compound, X, has a melting point of 71°C and a boiling point of 375°C.
Which statement about X is correct?
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Which method is used to obtain a concentrated solution of ethanol from a dilute solution of ethanol dissolved in water?
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Which definition of isotopes is correct?
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Which statement about a molecule of ammonia, $\text{NH}_3$, is correct?
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The electronic structures of atoms Q and R are shown.
[Image_1 showing electronic structures]
Q and R form an ionic compound.
What is the formula of the compound?
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What is the relative formula mass of aluminium oxide, $Al_2O_3$?
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Which products are initially obtained at each electrode during the electrolysis of concentrated aqueous sodium chloride?
[Table_1]
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Heat energy is produced when hydrocarbons burn in air. Which equations represent this statement?
1. $\text{C}_2\text{H}_5\text{OH} + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 3\text{H}_2\text{O}$
2. $\text{C}_2\text{H}_4 + 3\text{O}_2 \rightarrow 2\text{CO}_2 + 2\text{H}_2\text{O}$
3. $\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}$
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Which statements about exothermic and endothermic reactions are correct?
1. During an exothermic reaction, heat is given out.
2. The temperature of an endothermic reaction goes up because heat is taken in.
3. Burning methane in the air is an exothermic reaction.
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Which changes are physical changes?
1. melting ice to form water
2. burning hydrogen to form water
3. adding sodium to water
4. boiling water to form steam
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Which colour change is seen when hydrated cobalt(II) chloride is heated so that it becomes anhydrous cobalt(II) chloride?
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A student was investigating the reaction between marble chips and dilute hydrochloric acid.
Which changes slow down the rate of reaction?
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The reactions shown may occur in the air during a thunderstorm.
$N_2 + O_2 \rightarrow 2NO$
$2NO + O_2 \rightarrow 2NO_2$
$NO + O_3 \rightarrow NO_2 + O_2$
Which row shows what happens to the reactant molecules in each of these reactions? [Table_1]
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Three separate experiments are carried out on a solution of substance X.
1. A gas is produced when X is heated with ammonium chloride.
2. Methyl orange is yellow when added to X.
3. There is no reaction between X and sodium carbonate.
Which type of substance is X?
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Farmers spread slaked lime (calcium hydroxide) on their fields to neutralise soils that are too acidic for crops to grow well. Which ion in slaked lime neutralises the acid in the soil?
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Which salt preparation uses a burette and a pipette?
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Aqueous sodium hydroxide reacts with an aqueous solution of compound Y to give a green precipitate.
Aqueous ammonia also reacts with an aqueous solution of compound Y to give a green precipitate.
In each case the precipitate is insoluble when an excess of reagent is added.
Which ion is present in Y?
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Period 3 of the Periodic Table is shown.
What increases from left to right across Period 3?
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Which element is less reactive than the other members of its group in the Periodic Table?
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An element has the following properties.
• It forms coloured compounds.
• It acts as a catalyst.
• It melts at 1539°C.
In which part of the Periodic Table is the element found?
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Why are weather balloons sometimes filled with helium rather than hydrogen?
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Element E:
• forms an alloy
• has a basic oxide
• is below hydrogen in the reactivity series.
What is E?
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Which row shows how the metal reacts? [Table_1]
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Which statement about the extraction of iron from hematite is correct?
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Stainless steel is an alloy of iron and other metals. It is strong and does not rust but it costs much more than normal steel. What is not made from stainless steel?
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The diagram shows 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 pollutant gas cannot be produced by the combustion of fossil fuels (coal, petroleum and natural gas)?
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A farmer wrongly adds two substances to the soil at the same time. They react together to form a gas which turns damp red litmus blue. What are the two substances?
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In which process is carbon dioxide not formed?
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Two equations are shown.
reaction 1 \(\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2\)
reaction 2 \(\text{CaO} + \text{H}_2\text{O} \rightarrow \text{Ca(OH)}_2\)
Which terms describe reactions 1 and 2?
[Table_1]
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The structures of three substances are shown:
Why do these substances all belong to the same homologous series?
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Fuel oil, gasoline, kerosene and naphtha are four fractions obtained from the fractional distillation of petroleum. What is the order of the boiling points of these fractions?
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Which process produces alkenes from alkanes?
538
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Poly(ethene) is made from ethene. Ethene is ......1...... hydrocarbon because it contains a carbon to carbon ......2...... bond. The general name given to small molecules that undergo polymerisation is ......3...... . Which words complete gaps 1, 2 and 3?
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Which reaction is used to manufacture ethanol?
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Which statement about aqueous ethanoic acid is not correct?
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The diagram shows part of the molecule of a polymer.
Which diagram shows the monomer from which this polymer could be manufactured?
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