How many total molecules will be present when the reaction of 5,000 molecules of CS2 with 15,000 molecules of 0 2 goes to completion? CS2(1)+3 02(g) CO2(g) + 2S02(g)
(A) 5,000
(B) 10,000
(C) 15,000
(D) 20,000

(D) 20,000 .

Explanation:

Hello!

In this case, since the reaction between 15,000 molecules of oxygen with 5,000 molecules of CS2 is stoichiometrically correct, which means all the reactants are consumed and there is no excess reactant, we can infer that the total molecules once the reaction goes to completion are 20,000 because 5,000 molecules of CS2 react with exactly 15,000 molecules of oxygen are they are in a 1:3 mole ratio; therefore, we infer that based on the law of conservation of mass, the molecules are additive.

Therefore, answer is (D) 20,000 .

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