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A sample of ethanol is left in an open beaker at room temperature. After 24 hours, no ethanol remains in the beaker. What has happened to the ethanol?
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A gas is in a sealed container with a fixed volume. Which statements describe what happens to the molecules in the gas when the temperature is increased? 1. They move more slowly. 2. They collide with the walls of the container more frequently. 3. They collide with the walls of the container with less force. 4. They have greater kinetic energy.
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What happens when sodium atoms combine with chlorine atoms to form sodium chloride?
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The table shows some properties of four substances. [Table_1]
Which substances are ionic?
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Which statement about methane is correct?
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A sample of iridium has a relative atomic mass of 192.29. The sample contains two isotopes only. 64.50\% of the sample is $^{193}$Ir. What is the other isotope in the sample?
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Ammonium iron(III) citrate contains in its formula: - more than one ammonium ion - one iron ion - two $C_6H_4O_7^{4-}$ ions. What is the formula of ammonium iron(III) citrate?
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Silicon(IV) oxide reacts with chlorine and carbon to form liquid silicon(IV) chloride, SiCl_4, and carbon dioxide gas. If the reaction is carried out at r.t.p., which symbol equation represents this reaction?
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The structure of ethene is shown.
How many hydrogen atoms and how many carbon atoms are in one mole of ethene?
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A known volume and concentration of aqueous sodium hydroxide is titrated against dilute hydrochloric acid.
The volume of dilute hydrochloric acid needed to exactly neutralise the sodium hydroxide is measured.
Five calculation steps are shown.
1. Calculate the amount of hydrochloric acid in moles.
2. Calculate the relative formula mass of hydrochloric acid.
3. Calculate the concentration of hydrochloric acid in g/dm^3.
4. Calculate the amount of sodium hydroxide in moles.
5. Calculate the concentration of hydrochloric acid in mol/dm^3.
What is the order of these steps to calculate the concentration of the hydrochloric acid in g/dm^3?
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Two different substances are electrolysed using inert electrodes in two separate experiments. Hydrogen is produced in both experiments. Which row identifies the two substances and the electrode at which hydrogen is produced? [Table_1]
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Aqueous copper(II) sulfate can be electrolysed using either carbon electrodes or copper electrodes. Which statement describes what happens at the positive electrode?
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Which statement about a hydrogen–oxygen fuel cell is \textit{not} correct?
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Which reaction pathway diagram is correctly labelled?
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Which row describes a reaction where the overall energy change is exothermic? [Table_1]
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Which process involves a physical change only?
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In the Haber process, an equilibrium is established. $$\text{N}_2(g) + 3\text{H}_2(g) \rightleftharpoons 2\text{NH}_3(g)$$ The forward reaction is exothermic. Which change to the reaction conditions will move the position of equilibrium to the left?
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The flow chart shows some properties of a metal oxide. What is the metal oxide?
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Which statement about reactants in redox reactions is correct?
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Aluminium is extracted from aluminium oxide by electrolysis. The ionic half-equation for the reaction at one of the electrodes is shown. $$ \text{Al}^{3+} + 3e^- \rightarrow \text{Al} $$ Which row describes the change in oxidation number of the aluminium and the type of reaction at this electrode? [Table_1]
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Which statement about dilute hydrochloric acid is correct?
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Which row describes and gives the formula of hydrated copper(II) sulfate? [Table_1]
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The equations for three reactions are shown:
1. \( \text{Pb(NO}_3\text{)}_2(aq) + 2\text{KI}(aq) \rightarrow \text{PbI}_2(s) + 2\text{KNO}_3(aq) \)
2. \( 2\text{AgNO}_3(aq) + \text{CuI}_2(aq) \rightarrow \text{Cu(NO}_3\text{)}_2(aq) + 2\text{AgI}(s) \)
3. \( \text{CuO}(s) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{CuSO}_4(aq) + \text{H}_2\text{O}(l) \)
Which reactions are suitable for making a salt by precipitation?
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Acidified potassium dichromate(VI), $K_2Cr_2O_7$, is used to oxidise ethanol, $C_2H_5OH$.
The ionic equation for the reaction is shown.
$3C_2H_5OH + 2Cr_2O_7^{2-} + 16H^+ \rightarrow 3CH_3COOH + 4Cr^{3+} + 11H_2O$
Which properties of transition elements are shown by chromium in this reaction?
[Table_1]
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Which statements describe the Periodic Table?
1. The elements are arranged in order of their nucleon number.
2. The elements are arranged in order of their proton number.
3. It is used to predict the properties of elements.
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Which row shows the correct order of reactivity of the four named metals? [Table_1]
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Four iron nails are added to four different metal sulfate solutions. In which solution does a displacement reaction occur?
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A fertiliser contains ammonium nitrate and potassium phosphate. Why is the fertiliser described as an NPK fertiliser?
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What are the approximate percentages of oxygen and nitrogen in clean, dry air? [Table_1]
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Which compounds have similar chemical properties?
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Four statements about organic compounds P, Q, R and S are listed.
P is a saturated hydrocarbon.
The formula of Q is CH3CH3.
A molecule of R contains only one oxygen atom.
Compound S is a carboxylic acid.
Which statement about these compounds is correct?
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The structure of an organic compound is shown. What is the name of the compound?
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Which statement about the manufacture of ethene from larger alkane molecules is correct?
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Which processes are used to make ethanoic acid?
1. heating ethanol with acidified aqueous potassium manganate(VII)
2. bacterial oxidation of ethanol
3. distilling ethanol using a fractionating column
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Which statement about propene, $C_3H_6$, is correct?
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How many of each type of bond are present in ethanoic acid, CH$_3$COOH? [Table_1]
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Which diagram represents the structure of a protein?
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The chromatogram of substance S is shown. Some distances, W, X, Y and Z, are labelled on the diagram. How is the $R_f$ value of substance S calculated?
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Some information about solid silver chloride and solid sodium chloride is shown. \n \bullet Silver chloride and sodium chloride do \text{not} dissolve in kerosene. \n \bullet Silver chloride is insoluble in water, but sodium chloride is soluble in water. \n \bullet The boiling point of silver chloride is 1547\degree C and the boiling point of sodium chloride is 1413\degree C. \n \n Which processes are used to separate a mixture of solid silver chloride and solid sodium chloride?
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Which statement describes how a flame test is done?
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