Chemistry Question.

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@lil_killer129

10.4 Solid substances A and B react to form a solid product C and a gaseous product D. Solids A, B, and C are weighted, and the volume, temperature, and pressure of gas D are measured. From this and the ideal gas law, the number of moles of D are calculated. The data are:</p>

<p>mass A reacted: 5.00g mass of B reacted: 20.00g mass of C produced: 15.00g MOLES of D produced: 0.208 moles

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<p>Let's think this out. ;)</p>

<p>The first thing you have to remember is that mass is not lost during a reaction. Why else is there an equal amount of moles on both side of the reaction? ;)</p>

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@Reaction

The reaction seems to go as A+B -> C+D

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<p>Since mass is not lost, you can safely assume that (mass of A + mass of B) = (mass of C + mass of D).</p>

<p>With that in mind, the mass of D is 10. The question asks for molecular weight. In order to get it, it's simple now. The answer is (10g/0.208 moles), or A.</p>