No questions found
(a) Atoms are made of smaller particles called electrons, neutrons and protons.
Complete the table.
[Table_1: Particle Table]
particle relative charge relative mass
electron $\frac{1}{1840}$
neutron
proton +1
[2]
(b) The table gives information about atoms and ions \( A, B \) and \( C \).
Complete the table.
[Table_2: Atoms Table]
\begin{array}{cccc}
&\text{number of electrons}&\text{number of neutrons}&\text{number of protons}&\text{symbol}\\
A&\text{14}&\text{13}&{}_{13}^{27}\text{Al}\\
B&&\text{12}&{}_{12}^{25}\text{Mg}^{2+}\\
C&\text{10}&\text{10}&\text{9}
\end{array}
[6]
508
525
592
The table shows the melting points, boiling points and electrical conductivities of six substances D, E, F, G, H and I.
[Table]
Choose substances from the table which match the following descriptions. Each substance may be used once, more than once or not at all.
(a) Which substance is a liquid at 25°C? ............................................................................................. [1]
(b) Which substance is a gas at 25°C? ............................................................................................... [1]
(c) Which three substances contain simple molecules?
.................................................................................................................................................. [3]
(d) Which substance could be a metal? Give a reason for your answer.
substance ......................................................................................................................................
reason ...........................................................................................................................................
..................................................................................................................................................... [2]
(e) Which substance has a macromolecular structure? Give two reasons for your answer.
substance ......................................................................................................................................
reason 1 ........................................................................................................................................
reason 2 ........................................................................................................................................
[3]
(f) Which substance is an ionic solid? Give one reason for your answer.
substance ......................................................................................................................................
reason ...........................................................................................................................................
..................................................................................................................................................... [2]
502
549
584
(a) Name the ore of aluminium which mainly consists of aluminium oxide.
............................................................................................................................................... [1]
(b) Aluminium is produced by the electrolysis of aluminium oxide dissolved in molten cryolite.
(i) Give \textbf{two} reasons why the electrolysis is done using a molten mixture of aluminium oxide and cryolite instead of molten aluminium oxide only.
1 .................................................................................................................................................
2 ................................................................................................................................................. [2]
(ii) Write ionic half-equations for the reactions occurring at the electrodes.
positive electrode ..................................................................................................................
negative electrode .................................................................................................................. [2]
(iii) The anodes are made of carbon and have to be replaced regularly.
Explain why the carbon anodes have to be replaced regularly.
................................................................................................................................................. [2]
(c) The positions of some common metals in the reactivity series are shown.
(i) When magnesium is placed in aqueous copper(II) sulfate a displacement reaction occurs immediately.
Write an ionic equation for the reaction. Include state symbols.
................................................................................................................................................. [2]
(ii) State \textbf{two} observations you would make when magnesium is placed in aqueous copper(II) sulfate.
1 .................................................................................................................................................
2 ................................................................................................................................................. [2]
(iii) When aluminium foil is added to aqueous copper(II) sulfate no immediate reaction takes place.
Explain why.
................................................................................................................................................. [1]
(d) Aluminium powder reacts with iron(III) oxide to produce aluminium oxide and iron.
Write a chemical equation for this reaction.
................................................................................................................................................. [2]
555
526
529
This question is about phosphorus and compounds of phosphorus.
(a) A phosphorus molecule contains four phosphorus atoms only.
What is the formula of a phosphorus molecule?
............................................................................................................................ [1]
(b) Phosphorus reacts with chlorine gas to produce phosphorus(III) chloride, $\text{PCl}_3$.
(i) Write a chemical equation for the reaction between phosphorus and chlorine to produce phosphorus(III) chloride, $\text{PCl}_3$.
............................................................................................................................ [2]
(ii) Complete the dot-and-cross diagram to show the electron arrangement in a molecule of phosphorus(III) chloride, $\text{PCl}_3$. Show outer shell electrons only.
[2]
(c) Gaseous phosphorus(III) chloride, $\text{PCl}_3$, reacts with gaseous chlorine to form gaseous phosphorus(V) chloride, $\text{PCl}_5$.
$\text{PCl}_3(g) + \text{Cl}_2(g) \rightarrow \text{PCl}_5(g)$
The chemical equation for this reaction can be represented as shown.
(i) Use the bond energies in the table to calculate the energy change, in kJ/mol, of the reaction.
[Table_1]
• Energy needed to break bonds.
........................................ kJ
• Energy released when bonds are formed.
........................................ kJ
• Energy change of reaction.
energy change = ........................................ kJ/mol [3]
(ii) Deduce whether the energy change for this reaction is exothermic or endothermic. Explain your answer.
............................................................................................................................
............................................................................................................................ [1]
(d) Under certain conditions the reaction reaches equilibrium.
$\text{PCl}_3(g) + \text{Cl}_2(g) \rightleftharpoons \text{PCl}_5(g)$
State and explain the effect, if any, on the position of equilibrium if the pressure is increased. All other conditions are unchanged.
............................................................................................................................
............................................................................................................................
............................................................................................................................ [2]
(e) Phosphine, $\text{PH}_3$, is produced by the reaction between water and calcium phosphide, $\text{Ca}_3\text{P}_2$.
Balance the chemical equation for this reaction.
$\text{Ca}_3\text{P}_2 + .......\text{H}_2\text{O} \rightarrow ..........\text{Ca(OH)}_2 + ......\text{PH}_3$ [2]
(f) The phosphonium ion, $\text{PH}_4^{+}$, is similar to the ammonium ion.
(i) State the formula of the ammonium ion.
........................................................................... [1]
(ii) Suggest the formula of phosphonium iodide.
........................................................................... [1]
(g) Calcium phosphate contains the phosphate ion, $\text{PO}_4^{3-}$.
What is the formula of calcium phosphate?
............................................................................................................................ [1]
(h) Phosphorus forms another compound with hydrogen with the following composition by mass: P, 93.94\%; H, 6.06\%.
(i) Calculate the empirical formula of the compound.
empirical formula = .................................................. [2]
(ii) The compound has a relative molecular mass of 66.
Deduce the molecular formula of the compound.
molecular formula = .................................................. [1]
532
600
538
Nitrates such as ammonium nitrate are used as fertilisers.
The final stage in the production of ammonium nitrate is shown in the equation.
Ca(NO_3)_2 + 2NH_3 + CO_2 + H_2O → 2NH_4NO_3 + CaCO_3
Calculate the maximum mass of ammonium nitrate that can be produced from 820g of calcium nitrate, Ca(NO_3)_2, using the following steps.
The relative formula mass, $M_r$, of calcium nitrate, Ca(NO_3)_2, = 164.
• Calculate the number of moles of Ca(NO_3)_2 in 820g.
............................... mol
• Deduce the number of moles of NH_4NO_3 produced.
• Calculate the $M_r$ of NH_4NO_3.
............................... mol
$M_r$ of NH_4NO_3 = ...............................
• Calculate the maximum mass of ammonium nitrate produced.
............................... g [4]
536
573
582
This question is about sulfuric acid and substances that can be made from sulfuric acid.
(a) Sulfuric acid is a strong acid.
What is meant by the term strong acid?
strong .................................................................
acid ................................................................. [2]
(b) Dilute sulfuric acid and aqueous sodium hydroxide are used to make aqueous sodium sulfate, $\text{Na}_2\text{SO}_4$ (aq), or aqueous sodium hydrogen sulfate, $\text{NaHSO}_4$ (aq). The method includes use of the following apparatus.
!
$25.0\, \text{cm}^3$ of aqueous sodium hydroxide of concentration $0.100\, \text{mol/dm}^3$ was neutralised by $25.0\, \text{cm}^3$ of dilute sulfuric acid of concentration $0.0500\, \text{mol/dm}^3$. The equation for the reaction is shown. This is reaction 1.
$$2\text{NaOH}(aq) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{Na}_2\text{SO}_4(aq) + 2\text{H}_2\text{O}(l)$$ reaction 1
The same technique and the same solutions can be used to make aqueous sodium hydrogen sulfate. The equation for the reaction is shown. This is reaction 2.
$$\text{NaOH}(aq) + \text{H}_2\text{SO}_4(aq) \rightarrow \text{NaHSO}_4(aq) + \text{H}_2\text{O}(l)$$ reaction 2
Complete the table to calculate the volume of dilute sulfuric acid that reacts with $25.0\, \text{cm}^3$ of aqueous sodium hydroxide in reaction 2.
$$\begin{array}{|c|c|c|} \hline \text{volume of 0.0500 mol/dm}^3 & \text{volume of 0.100 mol/dm}^3 \\ \text{dilute sulfuric acid in cm}^3 & \text{aqueous sodium hydroxide in cm}^3 \\ \hline \text{reaction 1} & 25.0 & 25.0 \\ \text{reaction 2} & & 25.0 \\ \hline \end{array}$$ [1]
(c) Aqueous sodium hydrogen sulfate, $\text{NaHSO}_4$ (aq), contains the ions $\text{Na}^+$ (aq), $\text{H}^+$ (aq) and $\text{SO}_4^{2-}$ (aq).
Describe what you would see if the following experiments were done.
(i) A flame test was done on aqueous sodium hydrogen sulfate. ................................................................................................................... [1]
(ii) Solid copper(II) oxide was added to aqueous sodium hydrogen sulfate and the mixture was warmed.
.................................................................................................................
................................................................................................................. [2]
(d) A test can be done to show the presence of $\text{SO}_4^{2-}$ (aq) by adding acidified aqueous barium chloride or acidified aqueous barium nitrate.
(i) State the observation that would show that $\text{SO}_4^{2-}$ is present.
................................................................................................................... [1]
(ii) Write an ionic equation for the reaction that occurs if $\text{SO}_4^{2-}$ is present. Include state symbols.
................................................................................................................. [2]
541
596
568
Addition polymerisation and condensation polymerisation are two types of polymerisation.
(a) Which functional group is present in all the monomers which are used to make addition polymers? ............................................................................................................................................................... [1]
(b) Part of an addition polymer is shown.
CH₃ CH₃ CH₃ CH₃ CH₃ CH₃
| | | | | |
C------C------C------C------C------C------
| | | | | |
H H H H H H
(i) How many monomer units are needed to make the part of the addition polymer shown? .................................................................................................................................................. [1]
(ii) Draw the structure of the monomer that is used to make this addition polymer. Show all of the atoms and all of the bonds.
Name the monomer.
name ............................................................................................................................................... [2]
(iii) State the empirical formula of:
the monomer ..........................................................................................................................
the polymer. ........................................................................................................................ [2]
(c) Complex carbohydrates are natural condensation polymers. They can be broken down into colourless monomers which can then be separated and identified.
$ X $ is a complex carbohydrate.
Starting with a sample of $ X $, describe how to produce, separate, detect and identify the monomers which make it up.
Your answer should include:
- the name of the process used to break down $X$ into its monomers
- two types of substance that can be used to break down $X$
- the name of the process used to \textbf{separate} the monomers
- the method used to \textbf{detect} the monomers after they have been separated
- the method used to \textbf{identify} the monomers after they have been separated and detected. ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... ..................................................................................................................................................................... [6]
(d) Synthetic polyamides are condensation polymers.
(i) Name a synthetic polyamide. ......................................................................................................................................................... [1]
(ii) Synthetic polyamides can be made by reacting carboxylic acids with amines.
Name the other substance that is produced in this reaction. ............................................................................................................................................................................... [1]
599
564
528
