Determine the mass of oxygen in a 7.2-g sample of Al2(SO4)3
mols Al2(SO4)3 = grams/molar mass = ?
There are 12 O atoms per 1 mol Al2(SO4)3 so there are 12 x mols Al2(SO4)3 there.
Convert mols O to grams O. g = mols x 16 = ?
I assume the question means grams O (atoms) and not O2 (molecules).
To determine the mass of oxygen in a 7.2-g sample of Al2(SO4)3, we need to calculate the molar mass of Al2(SO4)3 and find the ratio of oxygen to the compound.
The molar mass of Al2(SO4)3 can be calculated by adding up the atomic masses of each element in the compound.
The atomic masses are:
Aluminum (Al) = 26.98 g/mol
Sulfur (S) = 32.06 g/mol
Oxygen (O) = 16.00 g/mol
Now, let's calculate the molar mass of Al2(SO4)3:
(2 x Al) + (3 x S) + (12 x O) = (2 x 26.98 g/mol) + (3 x 32.06 g/mol) + (12 x 16.00 g/mol) = 54.0 g/mol + 96.18 g/mol + 192.0 g/mol = 342.18 g/mol
The molar mass of Al2(SO4)3 is 342.18 g/mol.
Next, we can determine the number of moles of Al2(SO4)3 in the 7.2-g sample by dividing the mass of the sample by its molar mass:
Number of moles = Mass / Molar mass = 7.2 g / 342.18 g/mol
Number of moles ≈ 0.0210 mol (rounded to four decimal places)
In Al2(SO4)3, there are 12 oxygen atoms for every 1 molecule of Al2(SO4)3. So, to find the number of moles of oxygen, we multiply the number of moles of Al2(SO4)3 by 12:
Number of moles of oxygen = 0.0210 mol x 12 = 0.252 mol
Finally, we can calculate the mass of oxygen in the 7.2-g sample of Al2(SO4)3 by multiplying the number of moles of oxygen by the molar mass of oxygen:
Mass of oxygen = Number of moles of oxygen x Molar mass of oxygen = 0.252 mol x 16.00 g/mol
Mass of oxygen ≈ 4.03 g (rounded to two decimal places)
Therefore, the mass of oxygen in a 7.2-g sample of Al2(SO4)3 is approximately 4.03 grams.
To determine the mass of oxygen in a 7.2-g sample of Al2(SO4)3, you need to consider the molecular formula of the compound and the atomic masses of its constituent elements.
1. Determine the molar mass of Al2(SO4)3:
- Aluminum (Al) has a molar mass of 26.98 g/mol.
- Sulfur (S) has a molar mass of 32.07 g/mol.
- Oxygen (O) has a molar mass of 16.00 g/mol.
Multiply the respective atomic masses by their subscripts and sum them up:
(2 × 26.98 g/mol) + (3 × (32.07 g/mol + 4 × 16.00 g/mol)) = 2 × 26.98 g/mol + 3 × 96.27 g/mol = 27.86 g/mol + 288.81 g/mol = 316.67 g/mol
2. Calculate the molar mass of oxygen in Al2(SO4)3:
Oxygen (O) has a molar mass of 16.00 g/mol. Since there are three oxygen atoms in one molecule of Al2(SO4)3, multiply the molar mass of oxygen by three:
3 × 16.00 g/mol = 48.00 g/mol
3. Calculate the mass of oxygen in the 7.2-g sample of Al2(SO4)3:
To find the mass of oxygen, we need to use the molar mass ratio. Set up a proportion using the molar masses:
(Mass of oxygen / Molar mass of Al2(SO4)3) = (Mass of the sample / Molar mass of the sample)
Mass of oxygen = (Mass of the sample / Molar mass of the sample) × Molar mass of Al2(SO4)3
Mass of oxygen = (7.2 g / 316.67 g/mol) × 48.00 g/mol
Mass of oxygen ≈ 1.09 g
Therefore, the mass of oxygen in a 7.2-g sample of Al2(SO4)3 is approximately 1.09 grams.