No questions found
(a) Successive ionisation energies for the elements magnesium to barium are given in the table.
[Table_1]
(i) Explain why the first ionisation energies decrease down the group.
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................................................................................................................................. [3]
(ii) Explain why, for each element, there is a large increase between the 2nd and 3rd ionisation energies.
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.................................................................................................................................
................................................................................................................................. [2]
(b) A sample of strontium, atomic number 38, gave the mass spectrum shown. The percentage abundances are given above each peak.
(i) Complete the full electronic configuration of strontium.
1s^2 2s^2 2p^6 ........................................................................................................................ [1]
(ii) Explain why there are four different peaks in the mass spectrum of strontium.
.................................................................................................................................
................................................................................................................................. [1]
(iii) Calculate the atomic mass, $A_r$, of this sample of strontium. Give your answer to three significant figures.
$A_r$ = ................................. [2]
(c) A compound of barium, A, is used in fireworks as an oxidising agent and to produce a green colour.
(i) Explain, in terms of electron transfer, what is meant by the term oxidising agent.
.................................................................................................................................
................................................................................................................................. [1]
(ii) A has the following percentage composition by mass: Ba, 45.1; $Cl$, 23.4; $O$, 31.5.
Calculate the empirical formula of A.
empirical formula of A ....................................................... [3]
(d) Some reactions involving magnesium and its compounds are shown in the reaction scheme below.
(i) Give the formulae of the compounds X, Y and Z.
X ................................................................................................................................
Y ................................................................................................................................
Z ................................................................................................................................ [3]
(ii) Name the reagent needed to convert Y(s) into Z(aq) in reaction 1 and write an equation for the reaction.
reagent ..................................................................................................................
equation ................................................................................................................ [2]
(iii) How would you convert a sample of Z(s) into Y(s) in reaction 2?
................................................................................................................................. [1]
(iv) Give equations for the conversions of Mg into X, and Z(s) into Y.
Mg to X ................................................................................................................
Z to Y .................................................................................................................. [2]
586
519
571
(a) One way in which the sulfur dioxide for this reaction is produced is by heating the sulfide ore iron pyrites, FeS2, in air. Iron(III) oxide is also produced. Write an equation for this reaction.
............................................................................................................................................... [2]
(b) The sulfur trioxide produced in the Contact process is reacted with 98% sulfuric acid. The resulting compound is then reacted with water to produce sulfuric acid.
(i) Explain why the sulfur trioxide is not first mixed directly with water.
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................................................................................................................................................... [1]
(ii) Write equations for the two steps involved in the conversion of sulfur trioxide into sulfuric acid.
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................................................................................................................................................... [2]
(c) (i) Sulfur dioxide and sulfur trioxide both contain only S=O double bonds.
Draw labelled diagrams to show the shapes of these two molecules.
SO\textsubscript{2} ........................................................... SO\textsubscript{3}
................................................................................................................................................... [2]
(ii) For your diagrams in (i), name the shapes and suggest the bond angles.
SO\textsubscript{2} shape ........................................................... SO\textsubscript{3} shape ...........................................................
SO\textsubscript{2} bond angle ........................................................... SO\textsubscript{3} bond angle ........................................................... [2]
(d) The conversion of sulfur dioxide into sulfur trioxide is carried out at a temperature of 400\(^{\circ}\)C.
(i) With reference to Le Chatelier's Principle and reaction kinetics, state and explain one advantage and one disadvantage of using a higher temperature.
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................................................................................................................................................... [4]
(ii) State the expression for the equilibrium constant, $K_p$, for the formation of sulfur trioxide from sulfur dioxide.
$K_p =$ .......................................................................................................................................... [1]
(iii) 2.00 moles of sulfur dioxide and 2.00 moles of oxygen were put in a flask and left to reach equilibrium.
At equilibrium, the pressure in the flask was $2.00 \times 10^5$ Pa and the mixture contained 1.80 moles of sulfur trioxide.
Calculate $K_p$. Include the units.
$K_p =$ .................................
units = ................................. [5]
553
530
599
P, Q and R are structural isomers with the molecular formula C_4H_8.
All three compounds readily decolourise bromine in the dark.
P and Q do not exhibit stereoisomerism but R exists as a pair of geometrical (cis-trans) isomers.
All three compounds react with hot concentrated, acidified potassium manganate(VII) to produce a variety of products as shown in the table.
[Table_1]
| compound | products |
|---|---|
| P | CO2 and S (C3H6O) |
| Q | CO2 and CH3CH2CO2H |
| R | CH3CO2H only |
S reacts with 2,4-dinitrophenylhydrazine reagent, 2,4-DNPH, to form an orange crystalline product but does not react with Fehling’s reagent.
(a) Give the structural formulae of P, Q, R and S.
P .......................................................................... Q ......................................................................
R ......................................................................... S .................................................................... [4]
(b) (i) Explain what is meant by the term stereoisomerism.
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.........................................................................................................................................
......................................................................................................................................... [2]
(ii) Draw the displayed formulae of the geometrical isomers of R and name them both.
name ........................................................ name .............................................................. [2]
(c) State a reagent that could be used for the reduction of S and name the organic product of this reduction.
reagent .............................................................. product ........................................................ [2]
595
597
547
A series of reactions based on propanoic acid is shown.
(a) Write an equation for reaction 1, using [H] to represent the reducing agent. [2]
(b) (i) What type of reaction is reaction 2? [1]
(ii) Suggest a suitable reagent and conditions for reaction 2. [2]
(c) Write an equation for the reaction of propanoic acid with calcium carbonate, CaCO3. [2]
(d) (i) Suggest a suitable reagent and conditions for reaction 3. [2]
(ii) Identify the other product of reaction 3. [1]
530
583
510
