Answer 4.3.1: Why we need balanced chemical reactions

Problem:

The reaction between propane and hydrogen chloride to form propyl chloride and hydrogen is carried out in a continuous reactor. The product stream is analyzed and found to contain 27.45 mole% C₃H₇Cl, 27.45 mole % H₂ and 14.6% HCl. The feed to the reactor contains only propylene and hydrogen chloride. Calculate the fractional conversion of the limiting reactant and the percentage by which the other reactant is in excess. If the molar flow rate of the feed stream is 209 mol/s, what is the extent of reaction? (Give its numerical value and its units.)

Explanation:

We need balanced chemical reactions because we can't write the extents of reaction equations without them. Remember that we need to know the stoichiometry of the reaction to be able to write those?

We're going to have you do a few things first, before setting up the chemical reaction equations. First, you're going to match the names of the chemicals to their formulas so we can work with those. We've highlighted all the names of the chemicals listed in the problem statement in red and all the formulas given in blue. In the boxes below, match the number of the chemical name that appears in our problem statement as a species we need to have as a product or reactant with its formula:

	Put the numbers of the chemical names from the left column in the right places to match with the chemical formulas on the right. Some of your boxes should be empty when you are done because some of the chemicals are not involved in the reaction.
1) propyl		HCl
2) atomic hydrogen		H₂
3) hydrogen chloride		C₃H₇Cl
4) chloride		C₃H₇
5) propyl chloride		C₃H₈
6) molecular hydrogen		C₂H₅Cl
7) propane		H