Post Module Assessment

Science questions not covered in Chem 14A and 14B. Try to limit questions to chemistry (inorganic chemistry, physical chemistry, organic chemistry, biophysical chemistry, biochemistry, materials science, environmental chemistry).

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504986173
Posts: 3
Joined: Fri Sep 28, 2018 12:17 am

Post Module Assessment

Postby 504986173 » Tue Oct 02, 2018 5:59 pm

Hello, I am having trouble understanding how to work through this problem, as it is formatted differently than the problems explained in the module. The problem is as follows:


Question Title
20. How many moles of CO2(g) are produced when 1 kg of CaCO3(s) is used to neutralize an acid spill? The equation for the reaction at 1 atm and 25 degrees C is:
CaCO3(s) + H2SO4(aq) ---> CaSO4(s) + CO2(g) + H2O(l)

Is it just balancing the equation? Or do I have to go through all of the steps in the normal "find the limiting reactant" problem?

Lumbini Chandrasekera 1B
Posts: 63
Joined: Fri Sep 28, 2018 12:18 am

Re: Post Module Assessment

Postby Lumbini Chandrasekera 1B » Tue Oct 02, 2018 6:05 pm

So you don't have to balance the equation because it's already balanced and you also don't need to solve for the limiting reactant because we're not given the amount of H2SO4 there is so you can't even choose which one is limiting. you pretty much just use the 1 kg of CaCO3 in the question and use stoichiometry to solve for the amount of CO2 produced assuming that the CaCO3 is the limiting reactant and that there is an unlimited supply of H2SO4.

504986173
Posts: 3
Joined: Fri Sep 28, 2018 12:17 am

Re: Post Module Assessment

Postby 504986173 » Tue Oct 02, 2018 10:01 pm

Lumbini Chandrasekera 1B wrote:So you don't have to balance the equation because it's already balanced and you also don't need to solve for the limiting reactant because we're not given the amount of H2SO4 there is so you can't even choose which one is limiting. you pretty much just use the 1 kg of CaCO3 in the question and use stoichiometry to solve for the amount of CO2 produced assuming that the CaCO3 is the limiting reactant and that there is an unlimited supply of H2SO4.
So I just have to put a 10 in front of the CaCO3 and balance it from there?

Diego Gonzalez 3F
Posts: 32
Joined: Fri Sep 28, 2018 12:26 am

Re: Post Module Assessment

Postby Diego Gonzalez 3F » Tue Oct 02, 2018 10:21 pm

No, dont put a 10 in front of that, the equation is already balanced. Try converting kg to grams and then converting this to moles (using atomic # from periodic table) then compare stoichiometric coefficients to find the ratio from your reactant to product


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