If the arsenic is 76% and oxygen is 24% how would I calculate the chemical composition of of the oc=xide of arsenic that has been formed?

Divide 76 by the atomic weight of As (which is 74.92) and 24 by the atomic weight of O (which is 16.00). The two new numbers that you get will be in the ratio of As atoms to O atoms. That ratio is approximately 1 to 1.5, which is the same as 2 parts As to 3 parts O.

Take a 100 g sample.
that gives you 76 g As and 24 g O.

Determine mols.
76/atomic mass As = ??
24/16 = mols O = ??

Now make the smaller number 1(by dividing by itself), then divide the other number of that number also.
That will give you the subscripts. Post your work if you need further assistance.

So would the chemical composition be As203

yes

No, the chemical composition would not be As203. The correct chemical formula for the oxide of arsenic in this case would be As2O3.

Here's the breakdown of the calculation:

1. Determine the number of moles of arsenic (As) and oxygen (O) in the given sample:
- Moles of As: 76 g / atomic mass of As (74.92 g/mol) = 1.014 mol As
- Moles of O: 24 g / atomic mass of O (16.00 g/mol) = 1.5 mol O

2. Simplify the ratios of As to O atoms by dividing both values by the smaller value (1.014 mol As):
- Moles of As: 1.014 mol As / 1.014 mol As = 1 mol As
- Moles of O: 1.5 mol O / 1.014 mol As = 1.476 mol O

3. Convert the simplified ratios to whole numbers, which will represent the subscripts in the chemical formula:
- As: 1 mol As
- O: 1.476 mol O (rounded to the nearest whole number) = 1.5 mol O (rounded to the nearest half)

Therefore, the chemical composition of the oxide of arsenic formed in this case is As2O3, where there are two atoms of As and three atoms of O.