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Concentration Oi Worksheet #4

The document contains a series of chemistry problems related to titration and concentration calculations involving various reactions, including hydrochloric acid with sodium hydroxide, nitric acid with sodium carbonate, and the formation of hydrogen gas from magnesium and hydrochloric acid. It also discusses the production of sulfur from potassium dichromate and hydrogen sulfide, as well as the precipitation of barium sulfate from magnesium sulfate. Each problem requires calculations to determine concentrations, volumes, and masses of reactants and products.

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17 views5 pages

Concentration Oi Worksheet #4

The document contains a series of chemistry problems related to titration and concentration calculations involving various reactions, including hydrochloric acid with sodium hydroxide, nitric acid with sodium carbonate, and the formation of hydrogen gas from magnesium and hydrochloric acid. It also discusses the production of sulfur from potassium dichromate and hydrogen sulfide, as well as the precipitation of barium sulfate from magnesium sulfate. Each problem requires calculations to determine concentrations, volumes, and masses of reactants and products.

Uploaded by

whoa5530
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Download as DOCX, PDF, TXT or read online on Scribd
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CONCENTRATION OI

CONCENTRATION OI

1 A student carries out a titration experiment. They measured out 25.0 cm3 of hydrochloric acid into a
conical flask and put 0.100 mol/dm3 sodium hydroxide in the burette. 23.40 cm 3 of sodium hydroxide
was required for neutralisation. NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

Calculate the concentration of the hydrochloric acid. [3]

2 A teacher adds excess solid sodium carbonate to 50.0 cm3 of 0.200 mol/dm3 nitric acid.

Na2CO3(s) + 2HNO3(aq) → 2NaNO3(aq) + CO2(g) + H2O(l)

Calculate the volume of CO2 produced.

3 A students adds excess magnesium to 25.0 cm3 of hydrochloric acid.

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

45 cm3 of hydrogen gas was produced (measured at room temperature and pressure).

Calculate the concentration of the hydrochloric acid.

4- A students adds 0.366g zinc carbonate to 25cm3 of 0.05mol/dm3 nitric acid to form salt of zinc
nitrate .Calculate the excess reagent and the mass of zinc nitrate formed in the reaction .
CONCENTRATION OI

5 Following reaction can be used as a test for hydrogen sulphide.

K2Cr2O7(aq) + 4H2SO4(aq) + 3H2S(g) → Cr2(SO4)3(aq) + K2SO4(aq) + 7H2O(l) + 3S(s)

A student put 0.0200 mol/dm3 potassium dichromate(VI) (K2Cr2O7) in a beaker and added excess
sulfuric acid to acidify it. She then bubbled excess hydrogen sulphide through the acidified potassium
dichromate(VI) solution. 0.192 g of sulfur was produced. Calculate the volume of potassium
dichromate(VI) solution that was used. [3]

6 The test for Fe3+ ions is to add sodium hydroxide solution to a solution and look for the production of
an orange-brown precipitate of iron(III) hydroxide.

FeCl3(aq) + 3NaOH(aq) → Fe(OH)3(s) + 3NaCl(aq)

A student added excess iron(III) chloride solution to 2.00 cm3 of 0.100 mol/dm3 sodium hydroxide
solution. Calculate the mass of iron(III) hydroxide produced. [3]
CONCENTRATION OI

7 Fe2+ ions are oxidised by an acidified solution of potassium manganate(VII):

10FeSO4(aq) + 8H2SO4(aq) + 2KMnO4(aq) → 2MnSO4(aq) + 5Fe2(SO4)3(aq) + 8H2O(l) + K2SO4(aq)

A student put 25.0 cm3 of 0.0200 mol/dm3 KMnO4(aq) in a beaker and added excess sulfuric acid. They
then added iron(II) sulfate from a burette until the purple colour of the KMnO 4 disappeared completely.
28.30 cm3 of iron(II) sulafte solution was required for exact reaction.

Calculate the concentration of the iron(II) sulfate solution. [3]

8 Insoluble salts are made by precipitation. An equation for the preparation of barium sulfate is given
below. BaCl 2 (aq) + MgSO4 (aq) → BaSO4 (s) + MgCl 2 (aq)

This reaction can be used to fi nd x in the formula for hydrated magnesium sulfate MgSO 4 .xH2 O.

A known mass of hydrated magnesium sulfate, MgSO4 .xH2 O, was dissolved in water. Excess aqueous
barium chloride was added. The precipitate of barium sulfate was filtered, washed and dried. Finally it is
was weighed.
CONCENTRATION OI

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