# Hints for solving Stoichiometry Problems

This document was developed by S.E. Van Bramer for Chemistry 145 at Widener University.

## First the hamburger analogy

### My recipe for a bacon double cheeseburger is:

- 1 hamburger bun
- 2 hamburger patties
- 2 slices of cheese
- 4 strips of bacon

### Based on this recipe:

- If I have five bacon double cheeseburgers:
- How many hamburger buns do I have?
- How many hamburger patties do I have?
- How many slices of cheese do I have?
- How many strips of bacon do I have?

- How many bacon double cheeseburgers can you make if you start with:
- 1 bun, 2 patties, 2 slices of cheese, 4 strips of bacon
- 2 bun, 4 patties, 4 slices of cheese, 8 strips of bacon
- 1 dozen bun, 2 dozen patties, 2 dozen slices of cheese, 4 dozen strips of bacon
- 1 mole bun, 2 mole patties, 2 mole slices of cheese, 4 mole strips of bacon
- 10 bun, 20 patties, 2 slices of cheese, 40 strips of bacon

- If you had fixings for 100 bacon double cheeseburgers, but when you were cooking you ruined 10 of them. What percentage of the bacon double cheeseburgers do you actually make?

## Now, the chemistry problem.

**NOTE: The math and the concepts are identical to the above example. The only difference is the recipe. **

- Given 1 mole of NaCl
- Calculate the moles of sodium
- Calculate the moles of chloride
- Calculate the mass of sodium
- Calculate the mass of chloride
- Calculate the mass of sodium chloride

- Given 1 mole of methane (CH
_{4})
- Calculate the moles of carbon
- Calculate the moles of hydrogen
- Calculate the mass of carbon
- Calculate the mass of hydrogen
- Calculate the mass of methane

- Given 1 mole of ethanol (C
_{2}H_{6}O)
- Calculate the moles of carbon
- Calculate the moles of hydrogen
- Calculate the moles of oxygen
- Calculate the mass of carbon
- Calculate the mass of hydrogen
- Calculate the mass of oxygen
- Calculate the mass of ethanol

- Given 2 grams of ethanol (C
_{2}H_{6}O)
- Calculate the moles of carbon
- Calculate the moles of hydrogen
- Calculate the moles of oxygen
- Calculate the mass of carbon
- Calculate the mass of hydrogen
- Calculate the mass of oxygen
- Calculate the mass of ethanol

Please send comments or suggestions to svanbram@science.widener.edu
Scott Van Bramer

Department of Chemistry

Widener University

Chester, PA 19013

*© copyright 1996, S.E. Van Bramer*

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Last Updated: Saturday, May 18, 1996