Chemistry 9701/42 — May/June 2016

Cambridge A-Level · A Level Structured Questions · worked solutions for every part, with the mark scheme

questions

100

marks

120

minutes

Topics Transition Elements · Equilibria · Carboxylic Acids and Derivatives · Group 2 · Electrochemistry · Nitrogen Compounds · +7 more

Q1Transition ElementsGroup 2Free sample

(a)

Magnesium nitrate, $\text{Mg(NO}_3)_2$ , is very soluble in water. When a hot saturated solution of magnesium nitrate is cooled, crystals of the hydrate, $\text{Mg(NO}_3)_2 \cdot 6\text{H}_2\text{O}$ , are formed.

In the crystals, six water molecules bond to each $\text{Mg}^{2+}$ ion, and some of these water molecules are also bonded to the nitrate ions.

(i)

Suggest the type of bonding that occurs between

$\text{H}_2\text{O}$ and $\text{Mg}^{2+}$ , .....................................................................................................................

$\text{H}_2\text{O}$ and $\text{NO}_3^-$ . ....................................................................................................................

(ii)

Describe the arrangement of the water molecules around the $\text{Mg}^{2+}$ ion.

(iii)

Describe in detail what you would observe when crystals of $\text{Mg(NO}_3)_2 \cdot 6\text{H}_2\text{O}$ are heated in a boiling tube, gently at first and then more strongly.

Write equations for any reactions that occur.

(iv)

Calculate the percentage loss in mass when $\text{Mg(NO}_3)_2 \cdot 6\text{H}_2\text{O}$ is heated strongly to constant mass.

(b)

Explain why the Group 2 nitrates become more stable to heat down the group.

(c)

Magnesium nitrate and silver nitrate, $\text{AgNO}_3$ , decompose on heating to produce the same gases. Silver nitrate also produces silver metal during decomposition.

Write an equation for the decomposition of $\text{AgNO}_3$ .

The rest of this paper

9 more questions

Q2Equilibria · Carboxylic Acids and Derivatives · Electrochemistry14M
Q3Nitrogen Compounds · Halogen Compounds · Equilibria10M
Q4Transition Elements6M
Q5Transition Elements · Chemical Energetics8M
Q6Transition Elements · Analytical Techniques · Hydroxy Compounds · Carboxylic Acids and Derivatives8M
Q7Nitrogen Compounds · Analytical Techniques12M
Q8Group 2 · Chemical Energetics · Equilibria10M
Q9Introduction to A Level Organic Chemistry · Organic Synthesis · Hydrocarbons · Carboxylic Acids and Derivatives11M
Q10Transition Elements · Electrochemistry9M

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