Calcium carbonate is commonly used as a dietary supplement for patients with calcium deficiency
UOP CHM 109 Version 2 – Week 3 Exercises
Subject: Chemistry   / General Chemistry
Question
UOP CHM 109 Version 2 – Week 3 Exercises
Prepare written answers to the following exercises:
1. Calcium carbonate is commonly used as a dietary supplement for patients with calcium deficiency.
One way to prepare pure calcium carbonate is to combine calcium chloride, CaCl 2, with sodium
carbonate, Na2CO3.
. Provide the complete balanced equation and net ionic equation for this reaction
CaCl2(aq) + Na2CO3(aq) ? 2 NaCl(aq) + CaCO 3(s)
Why is calcium carbonate, instead of calcium chloride, commonly used as a source of dietary calcium
supplement?
Calcium carbonate is a dietary supplement used when the amount of calcium taken in the diet is not
enough. Calcium is needed by the body for healthy bones, muscles, nervous system, and heart.
Calcium carbonate also is used as an antacid to relieve heartburn, acid indigestion, and upset
stomach. It is available with or without a prescription.
2. Adapted from Exercise 102 in Ch. 7 of Introductory Chemistry:
As an environmental scientist, you may be asked to help revive lakes that have been acidified by acid
rain. Calcium carbonate (limestone) is commonly used for this application. It can neutralize the acids
(HNO3 and H2SO4) in acidic lakes by a process called liming.
You are asked by local community leaders to explain how this will work. To do so, you must provide
the ionic and net ionic equations for the reactions between calcium carbonate and HNO 3 and between
calcium carbonate and H2SO4 in your report.
CaCO3 (s) + H2SO4(aq) ———> CaSO4 + H2O + CO2 (g). Reaction is exothermic:- produces heat.
Write down the ionic and net ionic equations for the two reactions.
If the lake contains 1500 kg of HNO3 and 2000 kg of H2SO4, how much calcium carbonate must
be added to neutralize the lake?
3. Imagine that you work for a pharmaceutical company that makes aspirin (acetylsalicylic acid). Aspirin
is prepared by heating salicylic acid, C7H6O3, with acetic anhydride, C4H6O3. The other product is
acetic acid, C2H4O2.
C7H6O3 + C4H6O3 ? C9H8O4 + C2H4O2
The company just bought 2000 kg of salicyclic acid and 4000 kg of acetic anhydride to produce
aspirin. You are asked by your supervisor to provide answers to the following questions:
How many moles of salicyclic acid did the company just buy?
How many moles of acetic anhydride did the company just buy?
What is the theoretical yield (in kg) of aspirin that can be produced from the two compounds that
the company just bought?
The company cannot produce the maximum theoretical yield of aspirin. What are some possible
reasons for this inefficiency?
