M.2 Example in Textbook

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Cindy Nguyen 1L
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Joined: Fri Apr 06, 2018 11:04 am

M.2 Example in Textbook

Postby Cindy Nguyen 1L » Fri Apr 13, 2018 12:28 am

I was going over the example problem in the textbook and was confused on Step 3 (b).

The equation is CaC2(s) + 2 H2O(l) -> Ca(OH)2(aq) + C2H2(g). It's balanced.

We are asked if either 100g of water or 100g of calcium carbide is the limiting reactant, what mass of ethyne is produced, and what mass of excess reactant remains after the reaction is complete.

Step 1 converts the mass of each reactant into an amount in moles: 1.56 mol CaC2 and 5.55 mol H2O.
Step 2 calculates the theoretical amount of H2O needed to complete the reaction with the given amount of CaC2: 3.12 mol H2O.
Step 3 determines the limiting reactant: calcium carbide.
Step 3 (b) says "Because Ca2C2 is the limiting reactant and 1 mol CaC2 = 1 mol C2H2, the mass of ethyne that can be produced is
(100/64.10 mol CaC2) x (1 mol C2H4/ 1 mol CaC2) x 26.04 g(mol C2H4)^-1"

Where did Ca2C2 and C2H4 come from when the compounds are CaC2 and C2H2 in the formula?

Posts: 32
Joined: Fri Apr 06, 2018 11:03 am

Re: M.2 Example in Textbook

Postby LilianKhosravi_1H » Fri Apr 13, 2018 12:57 pm

I was wondering the same thing, I thought they might be typos?

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