Question
This question is about gases found in clean, dry air and gases found in polluted air.
(a) Name one gas found in clean, dry air which contributes to global warming.[1]
(b) State the percentage of nitrogen in clean, dry air.[1]
(c) Name the substance used to remove sulfur dioxide in flue gas desulfurisation.\([1]\)
(d) Nitrogen dioxide, \(\mathrm{NO}_2\), is formed in car engines.
Name the equipment in a car exhaust used to remove the \(\mathrm{NO}_2\) formed in car engines.[1]
(e) All gases diffuse.
(i) Choose from the list of formulae the gas which diffuses most quickly.
Draw a circle around your answer.
$
\begin{array}{lllll}
\mathrm{CO} & \mathrm{CO}_2 & \mathrm{CH}_4 & \mathrm{NO}_2 & \mathrm{SO}_2
\end{array}
$[1]
(ii) Explain your answer to (i).\([1]\)
(f) State one adverse effect of carbon monoxide on human health.\([1]\)
(g) Carbon dioxide, \(\mathrm{CO}_2\), is a reactant in photosynthesis.
Name the two products of photosynthesis.
…………………………………………………………………………..and…………………………………..[2]
(h) Complete the dot-and-cross diagram in Fig. 1.1 for a molecule of \(\mathrm{CO}_2\).
Show outer shell electrons only.
▶️Answer/Explanation
Ans:
(a) carbon dioxide 1
(b) 78 (%) 1
(c) calcium oxide
(d) catalytic converter
(e)(i) \(CH_{4}\)
(e)(ii) lowest relative molecular mass 1
(f) toxic
(g) M1 glucose
M2 oxygen
(h) M1 two dot-and-cross double bonds
M2 two pairs of non-bonding electrons on O and zero non-bonding electrons on C
Question
Lithium, sodium and potassium are Group I elements.
(a) Name the type of bonding in these elements…………………………………………………………………………………………………………………………….. [1]
(b) Sodium reacts with cold water to form hydrogen gas and a solution of a strong alkali.
(i) State the test for hydrogen gas.
test ……………………………………………………………………………………………………………………..
positive result ……………………………………………………………………………………………………….[1]
(ii) Suggest the pH of a solution of a strong alkali.pH = ………………………… [1]
(iii) Name a substance which can be used to confirm the pH of a solution of a strong alkali………………………………………………………………………………………………………………………. [1]
(iv) Write the symbol equation for the reaction between sodium and cold water.
Include state symbols………………………………………………………………………………………………………………………. [3]
(c) Lithium has two naturally occurring types of atoms, \({ }^6 \mathrm{Li}\) and \({ }^7 \mathrm{Li}\).
(i) State the name given to atoms of the same element with different nucleon numbers.
……………………………………………………………………………………………………………………… [1]
(ii) Complete Table 2.1 to show the number of protons, neutrons and electrons in the atom
and ion of lithium shown.
(iii) Table 2.2 shows the relative abundance of the two naturally occurring atoms of lithium.
Calculate the relative atomic mass of lithium to one decimal place.
relative atomic mass = ………………………… [2]
(d) Potassium oxide, \(\mathrm{K}_2 \mathrm{O}\), is an ionic compound.
Complete Fig. 2.1 to show the electronic configurations of the ions in potassium oxide. Show the charges on the jons.
▶️Answer/Explanation
Ans:
(a) metallic
(b)(i) lighted splint and (squeaky) pop
(b)(ii) 14
(b)(iii) universal indicator
b(iv)
$
2 \mathrm{Na}(\mathrm{s})+2 \mathrm{H}_2 \mathrm{O}(\mathrm{l}) \rightarrow 2 \mathrm{NaOH}(\mathrm{aq})+\mathrm{H}_2(\mathrm{~g})
$
M1 \(\mathrm{NaOH}\) as product in equation (1)
M2 fully correct equation (1)
M3 state symbols (1)
(c)(i) isotope(s)
(c)(ii)
each row ✔
(c)(iii)2$
\text { M1 }(6 \times 10)+(7 \times 90)(=690)
$
$
\text { M2 } 690 / 100=6.9 \text { (1) }
$
(d)M1 eight dots in third shell of both \(\mathrm{K}\) (1)
M2 six crosses and two dots in second shell of \(O\) (1)
M3 ‘ + ‘ charge on each \(\mathrm{K}\) on correct answer line and ‘2-‘ charge on \(\mathrm{O}\) ion on correct answer line (1)
Question
The Haber process is used to manufacture ammonia.
(a) State the main source of each gas used in the Haber process.
nitrogen……………………………………
hydrogen……………………………………….\([2]\)
(b) The equation for the Haber process is shown.
$
\mathrm{N}_2(\mathrm{~g})+3 \mathrm{H}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NH}_3(\mathrm{~g}) \quad \Delta H=-92 \mathrm{~kJ} / \mathrm{mol}
$
The reaction is reversible. The forward reaction is exothermic.
(i) State what is meant by the symbol \(\Delta H\).[1]
(ii) \(\Delta H\) for the forward reaction is \(-92 \mathrm{~kJ} / \mathrm{mol}\).
State why this value shows that the forward reaction is exothermic.\([1]\)
(iii) State the typical conditions and name the catalyst used in the Haber process.
temperature \({ }^{\circ} \mathrm{C}\)
pressure \(\mathrm{kPa}\)
catalyst……………………………[3]
(iv) Complete Table 3.1 to show the effect, if any, when the typical conditions in the Haber
process are changed. Use only the words increases, decreases or no change.
(v) Explain in terms of collision theory why increasing the temperature increases the rate of the reaction.[3]
(c) Ammonia reacts with an acid to form ammonium sulfate, \(\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4\).
(i) State the formula of the acid used.[1]
(ii) State one use of ammonium sulfate.[1]
(iii) Calculate the percentage composition by mass of nitrogen in \(\left(\mathrm{NH}_4\right)_2 \mathrm{SO}_4\).
percentage of nitrogen = …………………………. % [2] [Total: 18]
▶️Answer/Explanation
Ans:
3(a) nitrogen: air (1)
hydrogen: methane (1)
(b)(i) enthalpy change 1
(b)(ii) (the value of) ΔH is negative 1
(b)(iii) M1 450 (1)
M2 20 000 (1)
M3 iron (1)
(b)(iv) one mark for each of
(b)(v) M1 kinetic energy of particles increases (1)
M2 frequency of collisions between particles increases (1)
M3 higher percentage / proportion / fraction of collisions / particles have energy greater than / equal to activation energy (1)
or
more of the collisions / particles have energy greater than / equal to activation energy
(c)(i) \(\mathrm{H}_2 \mathrm{SO}_4\)
(c)(ii) fertiliser
Question
Copper is element 29 in the Periodic Table.
(a) Brass contains copper.
(i) Name the other metal in brass………………………………………………………………………………………………………………………. [1]
(ii) State the term given to a mixture of a metal with another element………………………………………………………………………………………………………………………. [1]
(b) Copper can be stretched into wires. Copper wires conduct electricity.
(i) Name the property of metals which means that they can be stretched into wires………………………………………………………………………………………………………………………. [1]
(ii) Name the particles responsible for the conduction of electricity in solid copper………………………………………………………………………………………………………………………. [1]
(c) Copper is a transition element.
Some physical and chemical properties of transition elements are shown.
physical properties:
● high density
● high strength
chemical properties:
● form coloured compounds
● have ions with variable oxidation numbers
(i) State one other physical property of transition elements………………………………………………………………………………………………………………………. [1]
(ii) State one other chemical property of transition elements………………………………………………………………………………………………………………………. [1]
(d) Hydrated copper(II) sulfate is a coloured compound. It exists as hydrated crystals which
contain water molecules.
(i) State the term given to water molecules present in hydrated crystals.
……………………………………………………………………………………………………………………… [1]
(ii) State the colour of hydrated copper(II) sulfate crystals………………………………………………………………………………………………………………………. [1]
(iii) Write the formula of hydrated copper(II) sulfate………………………………………………………………………………………………………………………. [2]
(e) Copper(II) oxide is formed when copper(II) nitrate, \(\mathrm{Cu}\left(\mathrm{NO}_3\right)_2\), is heated.
$
2 \mathrm{Cu}\left(\mathrm{NO}_3\right)_2(\mathrm{~s}) \rightarrow 2 \mathrm{CuO}(\mathrm{s})+4 \mathrm{NO}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g})
$
(i) State the class of oxide to which copper(II) oxide belongs.\([1]\)
(ii) State the meaning of the Roman numeral (II) in the name copper(II) oxide.[1]
(iii) 0.0200 moles of \(\mathrm{Cu}\left(\mathrm{NO}_3\right)_2\) is heated.
Calculate the mass of 0.0200 moles of \(\mathrm{Cu}\left(\mathrm{NO}_3\right)_2\).
$
\text { mass }=
$
(iv) Calculate the total volume of gas, in \(\mathrm{dm}^3\) at r.t.p., produced when 0.0200 moles of \(\mathrm{Cu}\left(\mathrm{NO}_3\right)_2\) is heated.
volume \(=\) \(\mathrm{dm}^3\) [2]
(v) Powdered aluminium reduces copper(II) oxide.
Write the symbol equation for this reaction………………………………………………………………………………………………………………………. [2][Total: 18]
▶️Answer/Explanation
Ans:
(a)(i) zinc
(a)(ii) alloy
(b)(i) ductility
(b)(ii) electrons
(c)(i) high melting point
(c)(ii) (act as) catalysts
(d)(i) water(s) of crystallisation
(d)(ii) blue
\begin{tabular}{ll}
4(d)(iii) & \(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}\) \\
& M1 \(\mathrm{CuSO}_4(1)\) \\
& M2 \(5 \mathrm{H}_2 \mathrm{O}(1)\)
\end{tabular}
(e)(i) basic
(e)(ii) the oxidation number of copper is +2
\begin{tabular}{ll}
4(e)(iii) & M1 \(M_{\mathrm{r}}\) of \(\mathrm{Cu}\left(\mathrm{NO}_3\right)_2=188(1)\) \\
& M2 \(=0.0200 \times \mathrm{M} 1=0.0200 \times 188=3.76 \mathrm{~g}\) (1)
\end{tabular}
(e)(iv) M1 moles of gas formed \(=0.0200 \times 5 / 2=0.05(00)\)
M2 volume \(=\) M1 \(\times 24.0=0.05(00) \times 24.0=1.2(0)(1)\)
e(v)
$
2 \mathrm{Al}+3 \mathrm{CuO} \rightarrow \mathrm{Al}_2 \mathrm{O}_3+3 \mathrm{Cu}
$
M1 correct products (1)
M2 rest of equation correct (1)
Question
Propane, propene, propan-1-ol and propanoic acid are members of different homologous series.
Molecules of these substances contain three carbon atoms.
(a) Explain why members of a homologous series have similar chemical properties…………………………………………………………………………………………………………………………….. [1]
(b) Name the homologous series to which propanoic acid belongs…………………………………………………………………………………………………………………………….. [1]
(c) State the general formula of the homologous series to which propanoic acid belongs…………………………………………………………………………………………………………………………….. [1]
(d) Propan-1-ol has an unbranched isomer.
● Name this isomer…………………………………………………………………………………………………………………………………..
● Draw the displayed formula of this isomer.\([2]\)
(e) Propane and propene can be manufactured by heating decane, \(\mathrm{C}_{10} \mathrm{H}_{22}\), in the presence of a catalyst. One other product is formed.
(i) Complete the equation for this reaction.
$
\mathrm{C}_{10} \mathrm{H}_{22} \rightarrow
$
$
……………………………………………+……………………………………………………$$
(ii) Name this manufacturing process.[1]
(f) Propene forms a polymer named poly(propene).
(i) Draw the displayed formula of a section of poly(propene) showing three repeat units.[2]
(ii) State the type of polymerisation that occurs when propene forms poly(propene).
……………………………………………………………………………………………………………………… [1](g) Propanoic acid reacts with aqueous sodium carbonate to form a salt.
(i) Suggest the name of the salt formed.
……………………………………………………………………………………………………………………… [1]
(ii) Suggest the formula of the anion in this salt………………………………………………………………………………………………………………………. [1]
(h) Propanoic acid forms an ester when it reacts with ethanol in the presence of a catalyst.
(i) Suggest a suitable catalyst………………………………………………………………………………………………………………………. [1]
(ii) Name the ester formed………………………………………………………………………………………………………………………. [1]
(iii) Draw the displayed formula of this ester.
▶️Answer/Explanation
Ans:
(a) same functional group
(b) carboxylic acids
e(i)
$
\begin{aligned}
& \mathrm{C}_{10} \mathrm{H}_{22} \rightarrow \mathrm{C}_3 \mathrm{H}_8+\mathrm{C}_3 \mathrm{H}_6+\mathrm{C}_4 \mathrm{H}_8 \\
& \mathbf{M 1} \mathrm{C}_3 \mathrm{H}_8+\mathrm{C}_3 \mathrm{H}_8(1)
\end{aligned}
$
M2 rest of equation correct (1)
(e)(ii) cracking 1
(f)(i) M1 six C atoms joined by single bonds in a chain and with continuation bonds (1)
M2 \(3 \times \mathrm{CH}_3\) at two \(\mathrm{C}\) intervals and whole structure correctly displayed (1)
(f)(ii) addition 1
(g)(i) sodium propanoate
g(ii) \(\mathrm{CH}_3 \mathrm{CH}_2 \mathrm{COO}^{-}\)
(h)(i) acid
or
any named inorganic acid, e.g. phosphoric acid
(h)(ii) ethyl propanoate 1
(h)(iii) M1 displayed formula of any ester linkage (1)
M2 correct structure of ethyl propanoate (1)