MYP 10 Chemistry 2012-13
DP Quantitative Chemistry
Name: _________________________________ ( )
Worksheet
Class: _________ Date: _____________
_________________________________________________________________________________
1. 0.600 mol of aluminium hydroxide is mixed with 0.600 mol of sulfuric acid, and the following reaction
occurs:
2Al(OH)
3
(s) + 3H
2
SO
4
(aq)

Al
2
(SO
4
)
3
(aq) + 6H
2
O(l)
(a) Determine the limiting reactant.
(b) Calculate the mass of Al
2
(SO
4
)
3
produced.
(c) Determine the amount(in mol) of the excess reactant that remains.
[(b)68.4g(c)0.200mol]
2. Aspirin, C
9
H
8
O
4
, is made by reacting ethanoic anhydride, C
4
H
6
O
3
(M r
= 102.1), with 2-hydroxybenzoic
acid (M r
= 138.1), according to the equation:
2C
7
H
6
O
3
+ C
4
H
6
O
3

2C
9
H
8
O
4
+ H
2
O
(a) If 15.0g of 2-hydroxybenzoic acid is reacted with 15.0 g ethanoic anhydride, determine the limiting reagent in this reaction.
(b) Calculate the maximum mass of aspirin that could be obtained in this reaction.
(c) If the mass obtained in this experiment was 13.7g, calculate the percentage yield of aspirin.
[(b) 19.6g (c)69.9%]
3. 14.48g of metal sulfate with the formula M
2
SO
4
were dissolved in water. Excess barium nitrate solution
was added in order to precipitate all the sulfate ions in the form of barium sulfate. 9.336g of precipitate
was obtained.
(a) Calculate the amount of barium sulfate BaSO
4
precipitated.
(b) Calculated the amount of sulfate ions present in the 14.48g of M
2
SO
4
.
(c) What is the relative molecular mass of M
2
SO
4
?
(d) Calculate the relative atomic mass of M and hence identify the meta.
[(a) 4.00 x 10 -2 moles (b) 4.00 x 10 -2 moles (c) 362 (d) A r
=133, Cs ]
4(a) Aqueous XO
4
3-
ions form a precipitate with aqueous silver ions. Write a balance equation for the
reaction, including state symbols.
(b) When 41.18 cm
3
of a solution of aqueous silver ions with a concentration of 0.2040 mol dm
-3
is
added to a solution of ions, 1.172g of the precipitates is formed.
(i) Calculate the amount (in moles) of Ag
+
ions used in the reaction.
(ii) Calculate the amount (in moles) of the precipitate formed.
(iii) Calculate the molar mass of the precipitate.
(iv) Determine the relative atomic mass of X and identify the element. [HL paper 2, Nov 03]
[(b)(i)8.401x10
-3 (ii)2.800x10
-3 (iii)418.6g/mol(iv)30.99,P]
5. 3.0g of impure Na
2
CO
3
.10H
2
O was dissolved to make 100 cm
3
of solution. 10.0 cm
3
was titrated
against HCl of concentration 4.38g dm -3 . 16.4 cm 3 of acid was needed for neutralisation.
(a) Calculate the number of moles of acid used.
(b) What is the number of moles of Na
2
CO
3
used in the titration?
(c) Calculate the concentration of the sodium carbonate solution in mol dm -3 .
(d) What is the percentage purity of the crystals?
[1.97 x 10 -3 , 9.84 x 10 -4 , 0.0984 moldm -3 ,93.8%]

6. Hydrated sodium carbonate has the formula Na
2
CO
3
.
n H
2
O. An experiment was performed to determine n , the amount of water of crystallisation. A sample of 50.00g of hydrated sodium carbonate was
dissolved in 250 cm 3 of water. 20.00 cm 3 of this solution reacted completely with 13.95 cm 3 of
2.00 mol dm
-3
hydrochlorc acid.
Na
2
CO
3
(aq) + 2HCl(aq)

2NaCl(aq) + CO
2
(g) + H
2
O(l)
(a) Calcuate the amount of hydrochlorc acid reacted.
(b) Calculate the amount of sodium carbonate in the 20 cm
3
of the solution used in the reaction.
(c) Calculate the concentration of sodium carbonate in the sample.
(d) Calculate the molar mass of the hydrated sodium carbonate.
(e) Calculate the value of n .
[(a)0.0279ml(b)0.01395mol(c)0.6975mol/dm 3 (d)286.75g/mol(e)10]
7. 0.375g of ethanedoic acid, (COOH)
2
.
x H
2
O is dissolved in distilled water to make 250 cm 3 of solution.
25.0 cm
3
of this ethanedoic acid solution required 30.00 cm
3
of a solution containing 0.340g dm
-3
of
hydroxide ions for complete neutralisation.
Calculate
(a) the concentration of anydrous ethanedoic acid in 1 dm
3
of the solution prepared above as mol dm
-3
and hence g dm
-3
.
(b) the mass of water associated with the amount of anhydrous ethanedoic acid in 1 dm
3
of the solution.
(c) the value of x in the formula. [ x = 2]
8(a) Aqueous XO
4
3-
ions form a precipitate with aqueous silver ions. Write a balance equation for the
reaction, including state symbols.
(b) When 41.18 cm
3
of a solution of aqueous silver ions with a concentration of 0.2040 mol dm
-3
is added
to a solution of ions, 1.172g of the precipitates is formed.
(i) Calculate the amount (in moles) of Ag + ions used in the reaction.
(ii) Calculate the amount (in moles) of the precipitate formed.
(iii) Calculate the molar mass of the precipitate.
(iv) Determine the relative atomic mass of X and identify the element.
[HL paper 2, Nov 03]
[(b)(i)8.401x10
-3 (ii)2.800x10
-3 (iii)418.6g/mol(iv)30.99,P]
9. 1.350g of an insoluble carbonate, MCO
3
, was dissolved in 250 cm
3
of a 0.203 mol dm
-3
hydrochloric
acid solution. The resulting solution was boiled to remove all the carbon dioxide produced. 25.0 cm
3
of
the solution was titrated with standard sodium hydroxide solution of concentration 0.100 mol dm
-3.
The
amount needed was 24.10 cm
3
. Deduce the identity of M. [Ca]