Empirical Formula Determination Through Combustion Reactions and Extra Credit Opportunity

Please complete the problem shown below. Have the solution ready to submit at the beginning of class on Friday, August 26th, 2010. To save time and effort on the problem, notice that the measured values are reported in milligrams. Therefore, feel free to work in the unit of millimole. The ratios all remain the same.

Also, if you would like 10 points extra credit towards your homework grade, bring in a 4-pack of AAA batteries. I will stockpile the batteries and if you need batteries for your calculator at any point this year, you can take a pack from the stockpile.

At the end of class today, there was a queston of what to do with decimals (fractions) once the moles of each element in the compound have been divided by the lowest mole value when determining an empirical formula. If a value is rougly nine tenths (X.9) or one tenth (X.1), then feel free to round up (X.9) or round down (X.1). For other decimals or fractions, use the examples below for how to convert the fraction to a whole number. Remember, elements combine in small whole numbers. **The use of "X" "Y" and "Z" are generic to represent any element.

• 1/2 --> (X .5)x2 --> {Example (Y2Z3.5 )2 --> Y4Z7}
• 1/3 --> (X .33)x3 --> {Example (Y1.33Z1)3 --> Y4Z3}
• 1/4 --> (X .25)x4 --> {Example (Y1.25Z1)4 --> Y5Z4}
• 1/5 --> (X .2)x5 --> {Example (Y1Z3.2)5 --> Y5Z16}
• 2/3 --> (X .67)x3 --> {Example (Y1Z2.67)3 --> Y3Z8}

The fractions represented above are the most common (if not only) fractions you will encounter when doing an empirical formula determination.