How many grams of oxygen are there exactly in 100.0 g of carbon dioxide?

100.0 g CO2 x (molar mass O2/molar mass CO2) = ? g O2 in 100.0 g CO2.

To calculate the number of grams of oxygen in 100.0 g of carbon dioxide, we need to use the molar mass and stoichiometry.

1. Start by determining the molar masses of carbon dioxide (CO2) and oxygen (O2).
- Carbon has a molar mass of 12.01 g/mol.
- Oxygen has a molar mass of 16.00 g/mol.

2. Determine the molar mass of carbon dioxide by adding the molar masses of carbon and oxygen:
Molar mass of CO2 = (molar mass of carbon) + 2 * (molar mass of oxygen)
Molar mass of CO2 = 12.01 g/mol + 2 * 16.00 g/mol
Molar mass of CO2 = 12.01 g/mol + 32.00 g/mol
Molar mass of CO2 = 44.01 g/mol

3. Now, we can calculate the number of moles of carbon dioxide in 100.0 g using its molar mass:
Moles of CO2 = (mass of CO2) / (molar mass of CO2)
Moles of CO2 = 100.0 g / 44.01 g/mol
Moles of CO2 = 2.27 mol (rounded to two decimal places)

4. Finally, we use the stoichiometric ratio between carbon dioxide and oxygen to find the number of moles of oxygen:
1 mol of CO2 -> 2 mol of oxygen
Moles of oxygen = (moles of CO2) * 2
Moles of oxygen = 2.27 mol * 2
Moles of oxygen = 4.54 mol (rounded to two decimal places)

5. To convert moles of oxygen to grams, multiply by the molar mass of oxygen:
Grams of oxygen = (moles of oxygen) * (molar mass of oxygen)
Grams of oxygen = 4.54 mol * 16.00 g/mol
Grams of oxygen = 72.64 g (rounded to two decimal places)

Therefore, there are exactly 72.64 grams of oxygen in 100.0 grams of carbon dioxide.