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E Multiple Choice Questions

The equation below shows two sets of reactions used to prepare a pure dry sample of lead (II) iodide from

lead (II) carbonate salts.

lead (II) carbonate lead (II) nitrate ----------------+ lead (II) iodide

solution R solution KI

From the equation, which of the following is not a step in the preparation of lead (II) iodide from lead (II)carbonate?

A. collect lead (II) iodide by filtrationB. filter offthe excess lead (II) carbonate

C. rinse the lead (II) iodide with deionised water

D. mix lead (II) carbonate with aqueous sodium nitrate solution

) Which of the following shows the most suitable combination of reactants to prepare a sample of the givensalt?

3. After precipitating barium sulfate, the precipitate is removed by filtration and water is poured onto the

filter paper. Why is water added to the residue?

A. to remove any dirt from the precipitate

B. to remove traces of the aqueous reactants

C. to speed up the drying process

D. to neutralise any unused acids or alkalis

4. When an excess of aqueous potassium iodide is added to the aqueous chloride of a transition metal,

XC/r, the following reaction occurs.

XC/r(aq) + 2KI(aq) -+ XIr(s) + 2KCl(aq)

XIr(s) + 2KI(aq) -+ KrXIo(aq)

A. carbonic acid and magnesium magnesium carbonate

B ammonium carbonate and hydrochloric acid ammonium chloride

C. magnesium nitrate and sulfuric acid magnesium sulfate

D. lead (II) oxide and hydrochloric acid lead (II) chloride

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Reactants Salt

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Which of the following shows how the mass of the precipitate varies with the volume of aqueous

potassium iodide added?

A. B.

mass mass

volume volume0

C.

MASS mass

volume volume0

In an ionic precipitation experiment in the laboratory,25.0 cm3 of 0.100 moVdm3 silver nitrate solution

was added to 25.0 cm3 of 0.100 mol/dm3 sodium chromate (VI) solution, based on the balanced chemical

equation below.

2AgNOr(aq) + NarCrOo(aq) -+ AgrCrOo(s) + 2NaNO,(aq)

What is the mass of the precipitate produced?

A. 0.415 g

B. 0.565 g

C. 0.830 g

D. 1.660 g

6. Which compound can be made by reacting a metal with a dilute acid?

A. magnesium hydroxide

B. copper (II) chloride

C. iron (III) sulfate

D. calcium carbonate

000

D.

000

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7 Two substances A and B are mixed in a beaker and the initial total mass is 100 g. The mass of the beaker

and its contents are recorded at regular intervals and the results obtained are shown in the graph below.

What are substances A and B?

mass of beaker+ contents

100 g

0 time

A. lead (II) nitrate and hydrochloric acid

B. copper (II) carbonate and sulfuric acid

C. magnesium ribbon and nitric acid

D. calcium carbonate and ethanoic acid

8. Sulfuric acid is not used to prepare carbon dioxide from limestone because

A. the reaction between sulfuric acid and limestone is irreversible.

B. sulfuric acid is dibasic and too strong for limestone.

C. an insoluble product which stops further reaction is formed.

D. the reaction between sulfuric acid and limestone is too vigorous.

9. In the reactivity series, metal Q is less reactive than hydrogen. The chloride of Q is soluble in water.

Which method could be used to prepare a pure sample of this salt?

A. Add an excess of metal Q to hydrochloric acid, filter and crystallise the salt.

B. Add aqueous potassium chloride to aqueous nitrate of Q, filter and collect the salt.

C. Add an oxide of Q to excess hydrochloric acid and crystallise the salt.

D. Add an excess of the carbonate of Q to hydrochloric acid, filter and crystallise the salt.

10. Which equation shows the most suitable reaction for the production of lead (II) sulfate in the school

laboratory with good yield?

A. Pb + HrSO, -+ PbSOo + H,B. Pb(OH), + HrSOo -+ PbSO4 + 2HrO

C. Pb(NO3), + H2SO4 + PbSO4 + 2HNO,

D. PbCO3 + HrSOo -+ PbSOo + CO, + HrO

11. Which of the following ionic equations best represents the reaction between silver nitrate solution and

aluminium iodide solution with the formation of a precipitate?

A. Ag.(aq) + I-(aq) -+ AgI(s)

B. A/3.(aq) + 3NOr-(aq) -+A/(NOr)r(s)

C. A/3t(aq) + 3l-(aq) +AIIr(s)D. Ag.(aq) +A/3'(aq) -+Ag,A/(s)

0

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12. The diagram below shows a titration experiment.

dilutehydrochloric acid

----------------

aqueous sodiumcarbonate containing

Universal Indicatorstart end-point

Which pH values in the table could be correct?

end-point

dilute hydrochloric acid aqueous sodium carbonate solution in conical ffask

A. 2 7 5

B. 2 9 7

C t2 1 9

D. 12 9 1

13. Salt PQ is to be prepared by reacting the carbonate of P with the acid HQ. The titration method is to be

used to carry out the reaction. What are the solubilities of the carbonate, acid and salt?

A. insoluble soluble insoluble

B. insoluble soluble soluble

C. soluble insoluble insoluble

D. soluble soluble soluble

Universal Indicatoris green

Salts

start

carbonate of P acid HQ salt PQ

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1

E Struchrred Questions

Rachel is tasked to prepare an insoluble salt in the school laboratory.

(a) She discovers that 25.0 cm3 of a sodium chloride solution requires 18.7 cm3 of 0.100 mol/dm3

silver nitrate solution for complete precipitation. Calculate the concentration of the sodium chloride

solution.

(b) State what will be observed when the two solutions are mixed.

(c) Describe the steps that she has to take to obtain a pure dry sample of the precipitate.

An experiment was conducted in the school laboratory to prepare silver chloride salt. Aqueous silver

nitrate was added to a metal chloride salt solution to obtain the precipitate of silver chloride.

(a) Describe the procedure used to obtain a pure dry sample of silver chloride.

(b) It was found that 10.0 cm3 of a 0.050 mol/dm3 solution of the chloride of a metal X required

10.0 cm3 of a 0.100 mofd63 silver nitrate solution for complete reaction. What is the formula of the

chloride?

(c) Is it possible to use an acid solution instead of a metal chloride salt solution to prepare silver chloride?

If it is, suggest an acid solution.

3. A student added 20.0 cm3 of 2.00 mol/dmt aqueous silver nitrate to a beaker containing 50.0 cm3 of1.00 mol/dmt aqueous sodium chloride. A precipitate of silver chloride was produced.

(a) (D What colour was the precipitate?

(iD How could the precipitate be separated from the solution?

(b) (i) How many moles of silver nitrate are there in 20.0 cm3 of 2.00 mol/dm3 aqueous silver nitrate?

(ii) How many moles of sodium chloride are there in 50.0 cm3 of 1.00 mol/dm3 aqueous sodium

chloride?

Sodium chloride reacts with silver nitrate according to the equation below.

AgNO, + NaC/ -+ AgC/ + NaNO,

(c) Using this equation and your answers in (b), calculate the mass of silver chloride produced in the

reaction.

(A. of Ag = 108 ; A,of Cl = 35.5)

(d) The experiment was repeated using 50.0 cmt of 1.00 moVdm3 aqueous silver nitrate with 20.0 cm3

of 2.00 moVdm3 sodium chloride. How does the mass of silver chloride produced compare with the

mass obtained in (c)? Explain your answer.

4. The reaction between barium nitrate and dilute sulfuric acid causes the formation of a precipitate.

(a) Name the precipitate.

A chemistry student conducted a series of experiments to find the masses of precipitate formed by using

two sets of solutions.

Solution X: 1.00 mol/dm3 of barium nitrate

Solution Y: 1.00 mol/dm3 of sulfuric acid

Increasing volumes of Y were added to separate boiling tubes containing a fixed volume of X.

The mixtures were stirred and the precipitates were removed by filtration. Each precipitate was washed

with water, dried and placed in a weighed container which was then reweighed.

)

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(b) Complete the final column to show the masses of the precipitates.

(c) Using the grid below, plot the mass of precipitate (y-axis) against the volume of Y (x-axis) and drawthe graph.

mass ofprecipitate /g

4 68volume of Y/cm3

r0 12 t4

2.5

2.0

r.5

1.0

0.5

20

(d) What was the volume of Y required to produce 1.50 g of precipitate?(e) Why was the mass of precipitate the same in the last three experiments?(f) Explain how the experiment shows that one mole of barium nitrate reacts with one mole of sulfuric

acid. Hence or otherwise, write the balanced chemical equation, with state symbols.(g) Determine the ionic equation for the above precipitation reaction.

l0 2 4.60 5.07 0.41

10 4 4.60 5.52 0.92

l0 6 4.60 6.01 1.41

l0 8 4.60 6.44

10 10 4.60 6.9s

l0 t2 4.60 6.95

10 t4 4.60 6.95

Salts47

The table below shows the results of the experiments.

Volume ofX/cmj

Volume ofY/cm3

Mass of emptycontainer/g

Mass of container+ precipitate/g

Mass ofprecipitate / g

i-.i.i.-j tr'.', :

''r'ii1-ii.i

-1-i I i-!f i. -L

- ii i#li-il --

+-;r-.:.firi{--.llIir-r-.i.-l

fir*i]-l+-!.1.-i

.i.r+i-i-T i i-i_i i 1iTH

i;:i I t-j.+.r--i -i i

TiT..t I :.1'i

1 i.+-i 'l-i i i

i,i i

,i: ;

'li-+ i.f-1 i +-+.+-+..i

-i-i.i..l.r-r i l.+ii

!t -r-.iLl ) i-r i-t- +-iiil 'r't-i-r

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5 The following procedure is an account of an experiment to determine the mass of copper (II) nitrate

crystals, Cu(NOr)r'3HrO, that can be obtained from a given quantity of nitric acid.

Procedure:

l. A measuring cylinder was used to transfer 125 cm3 of 2'00 mol/dm3 nitric acid to a beaker'

2. 12.0 g of copper (II) oxide was weighed out.

3. The acid was heated and the copper (II) oxide was added a little at a time, with stirring until all the

copper (II) oxide was present in excess.

4. The mixture was filtered and the filtrate was heated until the volume had been reduced to 50.0 cm3.

5. The solution was left to cool.

6. The crystals that formed were liltered off and dried between pieces of filter paper.

The mass of crystals obtained was 5.00 g.

(a) (i) Write a balanced chemical equation, with state symbols for the reaction.

(ii) Determine the number of moles of nitric acid that has reacted.

(iii) Determine the number of moles of copper (II) nitrate formed.

(iv) Calculate the relative molecular mass of copper (II) nitrate crystals, Cu(NOr)r'3HrO. Hence or

otherwise, determine the theoretical mass of crystals to be formed.

(b) In the described experiment:

(i) How would you know when copper (II) oxide is in excess?

(ii) Which measurement was unnecessary?

(iii) Why was the nitric acid heated?

(iv) Why did crystals of copper (II) nitrate form when the filtrate was cooled?

(v) Why were the copper (II) nitrate crystals dried between pieces of filter paper and not by heating

the crystals?

(vi) Suggest another compound that reacts with dilute nitric acid to give copper (II) nitrate.

(c) Suggest one way of modifying the experiment so as to obtain more than 5.00 g of copper (II) nitrate

crystals from 125 cm3 of 2.00 mol/dm3 nitric acid.

(d) (i) Explain why the mass of crystals formed was less than the calculated value.

(ii) Calculate the approximate mass of copper (II) nitrate crystals that will dissolve in 100 cm3 of

water at room temperature.

t

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