INORGANIC CHEMISTRY A2 TOPIC 21 REACTIONS OF PERIOD 3 ELEMENTS WITH WATER REACTIONS OF PERIOD 3 ELEMENTS WITH OXYGEN STRUCTURE AND BONDING OF PERIOD 3 OXIDES PERIOD 3 OXIDES WITH WATER ACID - BASE CHARACTER OF PERIOD 3 OXIDES STABILITY OF GROUP 4 OXIDATION STATES HYDROLYSIS OF GROUP 4 CHLORIDES DEFINITIONS AND ELECTRONIC CONFIGURATIONS BONDING IN COMPLEX IONS COLOUR OF COMPLEX IONS ISOMERISM LIGAND EXCHANGE REACTIONS DEPROTONATION THEORY REACTIONS OF CATIONS WITH OH - AND NH 3 OXIDATION STATES COLORIMETRY LIGAND EXCHANGE AND STABILITY CONSTANTS d-ORBITAL SPLITTING AND LIGHT ABSORPTION VANADIUM CHEMISTRY I VANADIUM CHEMISTRY II CHROMIUM CHEMISTRY I CHROMIUM CHEMISTRY II COBALT CHEMISTRY I Questionsheet 1 Questionsheet 2 Questionsheet 3 Questionsheet 4 Questionsheet 5 Questionsheet 6 Questionsheet 7 Questionsheet 8 Questionsheet 9 Questionsheet 10 Questionsheet 11 Questionsheet 12 Questionsheet 13 Questionsheet 14 Questionsheet 15 Questionsheet 16 Questionsheet 17 Questionsheet 18 Questionsheet 19 Questionsheet 20 Questionsheet 21 Questionsheet 22 Questionsheet 23 QUESTIONSHEETS A2 Level CHEMISTRY 10 marks 12 marks 16 marks 17 marks 14 marks 18 marks 14 marks 19 marks 17 marks 12 marks 19 marks 13 marks 18 marks 18 marks 8 marks 5 marks 20 marks 10 marks 15 marks 14 marks 15 marks 15 marks 21 marks www.curriculum-press.co.uk Curriculum Press • Bank House • 105 King Street • Wellington • Shropshire • TF1 1NU
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CHEMISTRY QUESTIONSHEETS A2 Level · a) Complete the following table to show the acid-base character of the oxides of elements in Period 3 of the Periodic Table. [4] b) For the oxides
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INORGANIC CHEMISTRYA2 TOPIC 21
REACTIONS OF PERIOD 3 ELEMENTS WITH WATER
REACTIONS OF PERIOD 3 ELEMENTS WITH OXYGEN
STRUCTURE AND BONDING OF PERIOD 3 OXIDES
PERIOD 3 OXIDES WITH WATER
ACID - BASE CHARACTER OF PERIOD 3 OXIDES
STABILITY OF GROUP 4 OXIDATION STATES
HYDROLYSIS OF GROUP 4 CHLORIDES
DEFINITIONS AND ELECTRONIC CONFIGURATIONS
BONDING IN COMPLEX IONS
COLOUR OF COMPLEX IONS
ISOMERISM
LIGAND EXCHANGE REACTIONS
DEPROTONATION THEORY
REACTIONS OF CATIONS WITH OH- AND NH3
OXIDATION STATES
COLORIMETRY
LIGAND EXCHANGE AND STABILITY CONSTANTS
d-ORBITAL SPLITTING AND LIGHT ABSORPTION
VANADIUM CHEMISTRY I
VANADIUM CHEMISTRY II
CHROMIUM CHEMISTRY I
CHROMIUM CHEMISTRY II
COBALT CHEMISTRY I
Questionsheet 1
Questionsheet 2
Questionsheet 3
Questionsheet 4
Questionsheet 5
Questionsheet 6
Questionsheet 7
Questionsheet 8
Questionsheet 9
Questionsheet 10
Questionsheet 11
Questionsheet 12
Questionsheet 13
Questionsheet 14
Questionsheet 15
Questionsheet 16
Questionsheet 17
Questionsheet 18
Questionsheet 19
Questionsheet 20
Questionsheet 21
Questionsheet 22
Questionsheet 23
QUESTIONSHEETS A2 LevelCHEMISTRY
10 marks
12 marks
16 marks
17 marks
14 marks
18 marks
14 marks
19 marks
17 marks
12 marks
19 marks
13 marks
18 marks
18 marks
8 marks
5 marks
20 marks
10 marks
15 marks
14 marks
15 marks
15 marks
21 marks
www.curriculum-press.co.uk
Curriculum Press • Bank House • 105 King Street • Wellington • Shropshire • TF1 1NU
Do notwrite inmargin
TOTAL /
A2 Level
10
REACTIONS OF PERIOD 3 ELEMENTS WITH WATERTOPIC 21 Questionsheet 1
a) (i) Describe what is observed when sodium is added to a beaker of cold water.
REACTIONS OF PERIOD 3 ELEMENTS WITH OXYGENTOPIC 21 Questionsheet 2
a) Complete the following table for the elements of Period 3.
b) Write the fully balanced equation for the reaction of the elements with oxygen.
(i) Na .......................................................................................................................................................... [1]
(ii) Mg ......................................................................................................................................................... [1]
(iii) Al ........................................................................................................................................................... [1]
(iv) Si ............................................................................................................................................................ [1]
(v) P ............................................................................................................................................................ [1]
PERIOD 3 OXIDES WITH WATERTOPIC 21 Questionsheet 4
a) On progressing from left to right across a period of the Periodic Table, what outstanding changes are observedin the behaviour of oxides with water? You should refer to three oxides of elements in either Period 2 (Li – F)or Period 3 (Na – Cl), and illustrate your answer by chemical equations.
b) When a non-metallic element forms more than one oxide, how do these oxides compare in their acidic character?Refer in your answer to the oxides of carbon and phosphorus, write chemical equations for their reactions (ifany) with water, and give the approximate pH values of the resulting solutions.
ACID - BASE CHARACTER OF PERIOD 3 OXIDESTOPIC 21 Questionsheet 5
a) Complete the following table to show the acid-base character of the oxides of elements in Period 3 of thePeriodic Table.
[4]
b) For the oxides of magnesium and aluminium, and one oxide of sulfur, write balanced chemical equations toillustrate the acid-base character you have described in a).
c) Write ionic equations, and apply the Bronsted-lowry theory or G.N.Lewis theory (or both), to explain thedifference in acid-base behaviour between magnesium oxide and the oxide of sulfur you have selected in b).
(ii) For each compound which you have described as an ‘oxidising agent’ or ‘reducing agent’, give oneexample of the compound behaving as such. (Balanced equations are not required, but you must indicateboth reactants and products.)
b) (i) Lead(II) chloride is largely unaffected by cold water, but tin(II) chloride behaves very differently. Describewhat is observed when tin(II) chloride is dissolved in water, write an equation for the reaction thatoccurs, and explain how this reaction can be prevented.
c) (i) Give the electron configuration of the following:
(ii) In what way is the electron configuration of both copper and chromium unusual compared with the otherfirst row of transition elements? Suggest why this occurs.
Example ................................................................................................................................................ [1]
Example ................................................................................................................................................ [1]
b) The hydrated chromium(III) ion, Cr3+(aq), is a cationic complex.
(i) State the shape of this ion and draw its structure
[3]
(ii) What type of bonding exists between the ligands and the chromium(III) ion?
(iv) Draw appropriate arrows in the following ‘boxes’ to represent orbital occupation in the hydratedchromium(III) ion. Label the diagram so as to distinguish between electrons possessed by the simple Cr3+
ion and those originating from the ligands.
[3]
Cr3+ [Ar]
4s3d 4p
TOPIC 21 Questionsheet 9
Do notwrite inmargin
TOTAL /
A2 Level
12
COLOUR OF COMPLEX IONS
a) Complete the following table:
ION Cr3+(aq) Mn2+(aq) Fe2+(aq) Fe3+(aq) Cu2+(aq)
COLOUR
[5]
b) (i) Give an example to show how, for a given metal in a and a given oxidation state, colour changes as theligands are changed.
4]Br (compound B) are isomeric compounds. Suggest two
simple tests which could be carried out in test tubes to distinguish between them.
Test 1Reagent ........................................................................................................................................................ [1]
Observation with compound A .................................................................................................................. [1]
Observation with compound B .................................................................................................................. [1]
Test 2Reagent ........................................................................................................................................................ [1]
Observation with compound A .................................................................................................................. [1]
Observation with compound B .................................................................................................................. [1]
b) There are five compounds of platinum(IV) chloride and ammonia, each containing a different octahedralcomplex ion. Details are given below.
(i) Draw the complex ions in compounds A, B, C and D.
[4]
(ii) Outline a simple experimental method to distinguish between compounds A, B, C and D.
a) Define the term ligand exchange reaction, as applied to the hydrated cations of transition elements, and givetwo reasons why such reactions may occur.
(iii) State the type of reaction occurring in a) (ii) and give the chemical functions of both the hydrated metalions and the water molecules.
Type of reaction ................................................................................................................................... [1]
Function of hydrated metal ions ........................................................................................................ [1]
Function of water molecules .............................................................................................................. [1]
b) On standing for several weeks, a solution of iron(III) chloride may deposit a small amount of iron(III) hydroxide.
(i) Write ionic equations (following on from that in a) (ii) ) to represent the formation of iron(III) hydroxide.
(ii) If OH- ions (e.g. from NaOH(aq)) are introduced into iron(III) chloride solution, iron(III) hydroxide isprecipitated copiously and immediately. How do you account for the difference?
c) The pH value of a solution formed by dissolving copper(II) sulfate in water differs from the pH of a solution ofiron(III) chloride, even when the molar concentrations of the hydrated cations are equal.
(i) Predict whether the copper(II) sulfate solution is acidic, neutral or basic, giving your reasoning.
(ii) Quote three examples from the first row of d-block elements to illustrate this statement, giving yourexpected observation and formula of the compound produced in each case.
Example 1 .................................................................................................................................................
Example 2 .................................................................................................................................................
Example 3 ............................................................................................................................................. [3]
b) NaOH(aq) and NH3(aq) behave very differently from each other when they are added to aqueous solutions of
transition element salts until they are eventually present in excess. Excess NaOH(aq) will dissolve some of thecompounds produced at first, while excess NH
3(aq) will dissolve others. Illustrate the differences in observations
and underlying chemistry by completing the following table.
Example of a compound which will dissolve
Reason for dissolving
Type of reaction occurring
Observation
Formula of the ion produced
[10]
c) (i) Name two compounds of p-block elements, produced by the action of NaOH(aq) on salt solutions, whichalso dissolve when the reagent is present in excess.
The above graph shows the results obtained when aqueous copper(II) sulfate and aqueous ammonia are mixedtogether in different proportions in the presence of ammonium sulfate. A complex is formed between ammoniaand the copper(II) ion, which has a different and much more intense colour than [Cu(H
2O)
6]2+.
(i) What volumes of 0.1 mol dm-3 CuSO4(aq) and 0.1 mol dm-3 NH
3(aq), when mixed together, give the highest
concentration of the complex?
Volume of 0.1 mol dm-3 CuSO4(aq) .........................................................................................................
Volume of 0.1 mol dm-3 NH3(aq) ......................................................................................................... [1]
a)
0 cm3 100 cm3
100 cm3 0 cm3
volume of 0.1 M CuSO4(aq)
volume of 0.1 M NH3(aq)
met
er r
eadi
ng
(ii) Calculate the mole ratio of Cu2+ : NH3 in the complex.
(a) Aqueous nickel(II) sulfate contains the [Ni(H2O)
6]2+ ion.
(i) The green nickel(II) sulfate turned blue when treated with aqueous ammonia. This blue solution whentreated with aqueous sodium cyanide turns yellow, but this yellow colour is unaffected by the addition ofexcess aqueous ammonia. Explain these observations, stating what is formed and why, but formulae ofany complex ions formed is not required.
(ii) When aqueous ethane-1,2-diamine was added to the blue solution described in part (i) (ie aqueous nickelsulfate and aqueous ammonia), it turned mauve. However, aqueous ethane-1,2-diamine had no effect onthe yellow solution described in part (i). Explain these observations, stating what is formed and why, butformulae of any complex ions formed is not required.
(ii) Zn2+ ..........................................................................................................................................................
Types of bonding..............................................................................................................................................
a) When the purple salt, chromium(III) nitrate-9-water, is dissolved in water, a blue-green solution A is obtained.With the help of an ionic equation, explain the colour change which occurs on dissolving.
b) Aqueous sodium hydroxide was added dropwise to a sample of A, followed by an excess of aqueous sodiumhydroxide to form solution B. What observations were made? Write ionic equations to describe the reactionsoccurring.
c) Zinc metal and aqueous hydrochloric acid were added to a sample of A. What colour change would be seento occur? Write an ionic half-equation to describe the reaction occurring to A.
d) To B was added aqueous sodium hydroxide and aqueous hydrogen peroxide. The solution was boiled. Thecolour of the solution became yellow. Excess hydrogen peroxide was then removed and the solution wasacidified. Finally, an orange colour formed.
(i) Name the chemical species responsible for the yellow colour.
(ii) Name the chemical species responsible for the orange colour and write a balanced ionic equation for itsformation from the yellow species.
Name ..................................................................................................................................................... [1]
CHROMIUM CHEMISTRY IIWhen an aqueous solution of chromium(III) chloride is evaporated at room temperature, violet crystals areformed (compound X). When a hot aqueous solution of chromium(III) chloride crystallises, pale green crystals(compound Y) are formed. When an excess of silver nitrate is added to 1 mole of either of these salts a whiteprecipitate of silver chloride is formed. Compound X forms 3 moles of silver chloride and compound Y formsonly 1 mole of silver chloride. Both compounds have the same composition by mass: 19.5% chromium, 40.1%chlorine and 40.4% water.
a) Calculate the empirical formula of both these salts.
a) Explain the meaning of the terms transition element, cationic complex and anionic complex, and illustrateyour answers with examples taken from the chemistry of cobalt.
Transition element ...........................................................................................................................................
Example ........................................................................................................................................................ [1]
Example ........................................................................................................................................................ [1]
Example ........................................................................................................................................................ [1]
b) Sketch the structures of two complex ions of cobalt(II), one of which has an octahedral shape and the otherone a tetrahedral shape.
[2]
c) State the type of bonding occurring between the central metal cation and a ligand. What structural featuremust a ligand possess for this type of bonding to occur?
Type of bonding ........................................................................................................................................... [1]
d) (i) Describe what you would observe if concentrated aqueous ammonia were added dropwise (until inexcess) to an aqueous solution of cobalt(II) nitrate.
(ii) Using your answer to d) (i), explain the meaning of the term ligand exchange reaction. Include in yourexplanation the chemical equation for the reaction involved.