Name: _________________________
IB Chemistry 11
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Worksheet - Quantitative Chemistry (Stoichiometry)
Part I - Short Answer
1. Communicate your knowledge and understanding in a clear and logical manner.
2. In questions involving calculation, full marks will not be given for providing only an answer.
3. Show all work neatly on the paper provided. Indicate your final answer with a box around it.
1. How many grams of ammonia gas are produced when 14 g of nitrogen gas is reacted with an
unlimited supply of hydrogen gas?
(4)
2. 25.0 cm3 of 0.200 mol dm–3 ethanoic acid was added to 30.0 cm3 of a 0.150 mol dm–3
sodium hydrogencarbonate solution, NaHCO3(aq).
(a) State an equation for the reaction of ethanoic acid with a solution of sodium
hydrogencarbonate.
(b) Determine which is the limiting reagent. Show your work.
(c) Calculate the mass, in g, of carbon dioxide gas produced.
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3. In an experiment, a strip of copper wire was placed into a solution of silver nitrate. The copper
wire began to dissolve and a precipitate of solid silver was formed and collected from the solution
using a filter paper. Use the lab data below, along with the chemical equation, to answer the
following questions.
AgNO3(aq) +
Cu(s) ----->
Ag(s) +
Cu(NO3)2(aq)
(work done here will not be marked)
Initial mass of Cu wire.......................9.80 g
Final mass of Cu wire.......................4.32 g
Mass of filter paper only...................1.13 g
Mass of filter paper and silver...........18.59 g
a) What mass of copper wire was used?
b) What mass of silver was produced?
c) Theoretically, what should have been the mass ofsilver produced?
d) Using the theoretical and actual values of silver produced, calculate
the percentage yield for this experiment.
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(1)
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4. Use the following chemical equation to answer the questions below.
Mg3N2(s) + H2O(l) ----> MgO(s) + NH3(g)
(work done here will not be marked)
In the reaction, 8.6 g of magnesium nitride reacts with 8.6 g of water.
a) What is the limiting reagent?
b) What is the amount of excess (in grams), of the other chemical?
c) Based on the limiting reactant, how many grams of ammonia would
be produced?
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Use the following data for solutions to the next 6 questions (5 to 10).
Students reacted ICl(l) with CsBr(s) to form a
yellow solid, CsICl2(s), as one of the products.
CsICl2(s) has been found to produce very pure
CsCl(s) which is used in cancer treatment. To
confirm the composition of the yellow solid,
the students determined the amount of iodine
in 0.2015 g of CsICl2(s) by titrating it with
0.0500 mol dm–3 Na2S2O3(aq). The data
on the right was recorded for the titration.
The overall reaction taking place during the titration is:
5. Calculate the percentage of iodine by mass in CsICl2(s), correct to three significant digits (1)
6. State the volume, in cm3, of 0.0500 mol dm–3 Na2S2O3(aq) used in the titration.
(1)
7. Determine the amount, in mol, of 0.0500 mol dm–3 Na2S2O3(aq) added in the titration.
(1)
8. Calculate the amount, in mol, of iodine atoms, I, present in the sample of CsICl2(s).
(1)
9. Calculate the mass of iodine, in g, present in the sample of CsICl2(s).
(1)
10. Determine the percentage by mass of iodine in the sample of CsICl2(s), correct to three significant
figures, using your previous responses.
(1)
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