No questions found
(a) A sample of barium is heated in oxygen.
(i) Describe two observations for this reaction.
[2]
(ii) Write an equation for this reaction. Include state symbols.
[1]
(b) Calcium carbonate can be converted into calcium hydroxide in a two-step process.
(i) Describe how the two-step process is carried out to convert calcium carbonate into calcium hydroxide. Include relevant equations.
[3]
(ii) Name the type of reaction occurring when calcium carbonate is converted into calcium oxide.
[1]
(iii) State one common use for both calcium carbonate and calcium hydroxide.
[1]
(c) Gallium is a silver-grey solid. Aluminium and gallium share many similar chemical properties.
(i) Construct an equation for the reaction of gallium when heated in oxygen to form gallium oxide, $Ga_2O_3$.
[1]
(ii) Deduce the oxidation number of gallium in $Ga_2O_3$.
[1]
(iii) Complete the table by predicting the formula of each gallium-containing product formed when gallium oxide reacts separately with hot aqueous hydrochloric acid and with hot concentrated sodium hydroxide.
[Table_1]
[2]
526
543
544
(a) Explain what is meant by the term relative isotopic mass.
..................................................................................................................................
..................................................................................................................................
.................................................................................................................................. [2]
(b) A sample of copper contains two isotopes, $^{63}\text{Cu}$ and $^{65}\text{Cu}$. The relative atomic mass of the copper in this sample is 63.55.
Calculate the percentage abundance of each of these isotopes. Show your working.
percentage abundance of $^{63}\text{Cu}$ = ............................ %
percentage abundance of $^{65}\text{Cu}$ = ............................ % [2]
(c) (i) Name the type of bonding within a sample of solid copper.
.................................................................................................................................. [1]
(ii) Draw a labelled diagram to show the bonding within a sample of solid copper.
[2]
(iii) State the electronic configuration of a copper atom.
$1s^2$ ......................................................................................................................... [1]
(d) A student is provided with a sample of hydrated copper(II) sulfate, $\text{CuSO}_4\cdot x\text{H}_2\text{O}$, and is asked to determine the value of $x$.
The student dissolves a sample of the hydrated copper(II) sulfate in water and adds it to an excess of aqueous potassium iodide to make a total volume of $250.0 \text{cm}^3$ of solution.
$2\text{CuSO}_4 + 4\text{KI} \rightarrow 2\text{CuI} + \text{I}_2 + \text{K}_2\text{SO}_4$
The amount of iodine produced during this reaction is found by titrating a sample of this solution with sodium thiosulfate solution.
$25.0 \text{cm}^3$ of the iodine-containing solution requires $20.0 \text{cm}^3$ of $0.10 \text{mol dm}^{-3}$ sodium thiosulfate solution.
$\text{I}_2 + 2\text{S}_2\text{O}_3^{2-} \rightarrow \text{S}_4\text{O}_6^{2-} + 2\text{I}^-$
(i) Calculate the amount, in mol, of copper(II) sulfate present in the original sample of hydrated copper(II) sulfate.
Show your working.
amount of copper(II) sulfate = .......................... mol [2]
(ii) A total of $7.98 \text{ g of CuSO}_4$ is present in $10.68 \text{ g of CuSO}_4\cdot x\text{H}_2\text{O}$.
Complete each row of the table to calculate the value of $x$, where $x$ is an integer.
$[M_r: \text{CuSO}_4, 159.6]$
| amount of CuSO$_4$ in 10.68 g of CuSO$_4\cdot x$H$_2$O | ........................ mol |
| amount of H$_2$O in 10.68 g of CuSO$_4\cdot x$H$_2$O | ........................ mol |
| value of x | x = ........................ |
[3]
562
544
600
(a) (i) Suggest a name for the reaction that occurs when sucrose reacts with water to form glucose and fructose.
........................................................................................................................................................... [1]
(a) (ii) If no catalyst is added in reaction Z, the reaction is very slow.
Label the Boltzmann distribution to show the effect of adding a catalyst to the sample of sucrose and water molecules at constant temperature.
Explain your labelled diagram.
...............................................................................................................................
...............................................................................................................................
............................................................................................................................... [3]
(b) (i) Both fructose and glucose contain chiral centres.
Explain what is meant by the term chiral centre.
........................................................................................................................................................... [1]
(b) (ii) On the diagram of the fructose molecule, label all the chiral centres with an asterisk (*).
[1]
(b) (iii) Determine the empirical formula of fructose.
........................................................................................................................................................... [1]
(c) (i) Explain what is meant by the term enthalpy change of combustion.
...............................................................................................................................
............................................................................................................................... [2]
(c) (ii) Write the equation for the complete combustion of sucrose.
........................................................................................................................................................... [1]
(c) (iii) Use the data in the table to calculate the enthalpy change for the reaction occurring when sucrose reacts with water, $\Delta H_{r}$. You should draw a labelled Hess’ cycle to show your working.
[Table_1]
$\Delta H_{r}$ = .............................. kJ mol⁻¹ [2]
525
568
549
Hexane, $C_{6}H_{14}$, is a colourless liquid.
Two test-tubes contain equal amounts of hexane. $1\text{ cm}^{3}$ of bromine, $Br_{2}(aq)$, is added to both test-tubes. One test-tube is kept in the dark and the other is exposed to sunlight.
The table describes the appearance of each test-tube after one hour.
[Table_1]
(a) The test-tube in the dark is kept cool and is not exposed to ultraviolet light.
Explain the observations for the test-tube kept in the dark.
..........................................................................................................................
......................................................................................................................... [2]
(b) In sunlight, bromine reacts with hexane by a mechanism which occurs via a series of steps.
(i) State the name of the mechanism of the reaction that occurs.
.......................................................................................................................... [1]
(ii) Give an equation which shows a propagation step in this reaction in which hexane produces $\cdot C_{6}H_{13}$.
.......................................................................................................................... [1]
(iii) Give an equation which shows a propagation step in this reaction that produces 1-bromohexane.
.......................................................................................................................... [1]
(iv) Give an equation which shows a termination step in this reaction that produces 1-bromohexane.
.......................................................................................................................... [1]
(c) $A$ and $B$ are different straight chain alkenes with molecular formula, $C_{6}H_{12}$.
$A$ does not show stereoisomerism.
$A$ reacts with potassium manganate(VII) to form hexane-1,2-diol.
(i) Draw the structural formula of $A$.
[1]
(ii) State the conditions needed for this reaction of $A$.
......................................................................................................................... [2]
(d) $B$ reacts with hydrogen gas in the presence of a platinum catalyst to produce hexane.
(i) Name the type of reaction occurring.
.......................................................................................................................... [1]
(ii) In terms of $\sigma$ and $\pi$ bonds, describe any similarities and differences in the type of carbon-carbon bonds in $B$ and the type of carbon-carbon bonds in hexane.
..........................................................................................................................
.........................................................................................................................
......................................................................................................................... [2]
600
534
511
C, D and E are isomers of each other.
They are made by passing an alcohol vapour over an aluminium oxide catalyst.
(a) (i) Name the type of reaction occurring.
...................................................................................................................... [1]
(ii) Draw the displayed formula of the alcohol used in this reaction. [2]
(iii) Name the isomers C, D and E.
[Table_1]
isomer | name
C |
D |
E |
[2]
(b) F is an organic molecule which has the molecular formula $C_3H_6O_2$.
When F is heated with NaOH(aq) followed by H$_2$SO$_4$(aq) the products G and H are made.
Separate samples of G and H are added to
- Na$_2$CO$_3$(aq)
- sodium metal
- alkaline aqueous iodine.
The observations are described in the table.
[Table_2]
reagent(s) | G | H
Na$_2$CO$_3$(aq) | colourless bubbles of gas produced | no visible reaction
Na(s) | colourless bubbles of gas produced | colourless bubbles of gas produced
alkaline aqueous iodine | no visible reaction | yellow precipitate forms
(i) Complete the table to identify the functional groups present in F, G and H.
[Table_3]
functional group
F |
G |
H |
[3]
(ii) Name the yellow precipitate formed when alkaline aqueous iodine reacts with H.
...................................................................................................................... [1]
(iii) Draw the structures of G and H.
[2]
501
524
574
