1. Observe: The first question is: “How many moles of carbon monoxide (CO) are required to
react completely with 1.75 moles of iron (III) oxide (Fe2O3)?” (If this is not the question you
see, click New question until i
...
1. Observe: The first question is: “How many moles of carbon monoxide (CO) are required to
react completely with 1.75 moles of iron (III) oxide (Fe2O3)?” (If this is not the question you
see, click New question until it appears.)
A. What unit is given in the question? 1.74 Moles of iron (III) oxide
B. What quantity is asked for? Moles of carbon dioxide
2. Find: Look for the conversion factor that contains the units “mol Fe2O3” on top and “mol CO”
on the bottom. Drag the tile containing this factor down to the green strip at the bottom.
According to the tile, how many moles of CO react with one mole of Fe2O3? 5.2 moles of CO
3. Analyze: To get an answer in moles of CO, you need to cancel the moles of Fe2O3. Turn on
Show units.
A. What units are given to the right of the equals sign? (mol Fe2O3) + (mol Fe2O3)/ mol
CO
B. If these aren’t the units you want, click Flip tile. What unit is given now? Mol CO
Activity B (continues below)
4. Calculate: If the units are correct, multiply or divide the numbers to solve the problem.
Activity B:
Canceling units
A. How many moles of CO will react with 1.75 moles of Fe2O3? 5.25 moles
B. Turn on Show numerical result. Were you correct? Yes
5. Practice: Turn off Show units and Show numerical result. Click New question, and use
what you’ve learned to solve another stoichiometry problem. For each problem, list the units
given, the units asked for, and the solution.
The problems in the Gizmo are given in random order, so you may have to click Next
question several times to see a new problem. (Note: Each term in the equation is either a
solid (s), liquid (l), gas (g), or an aqueous solution (aq).)
If you are stuck, try one of the following hints:
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