Follow this example to do question 3
A compound is made up of:
Step 1
Convert to moles of atoms,
|
|
|---|
| grams <==> moles |
| aluminum | (1.99 g / 26.982 g/mole) = 0.07375 mole Al |
| oxygen | (1.76 g / 15.999 g/mole) = 0.1100 mole O |
Step 2
Divide the number of moles of each element by the smallest of the mole ratios calculated.
Here, we will divide by 0.07375 moles.
| Al: | 0.07375 mole / 0.07375 mole = 1.00 |
| O: | 0.1100 mole / 0.07375 mole = 1.49 |
Change the mole ratios in Step 2 to the smallest set of whole numbers.
| Al: | 1.00 x 2 =2 |
| O: | 1.49 x 2 =3 |