mass of mg- .28
mass of o- .41
calculate the moles of mg and o
what is the simples whole number ratio of the moles of mg to the moles of o? round off to the nearest whole number ratio. use this mole ratio to write the empirical formula.
the molecular mass of magnesium oxide is found to be 40.3 g/mol. what isthe molecular formula?
O weighs 16 grams/mole
Mg weighs 24.3 g/mole
if it were MgO it would be 16+24.3 = 40.3 grams/mole so that is what it is
Now I suspect your real question was if you have .28 grams of Mg and .41 grams of O in a compound, what is the compound?
Mass Of Mg/ molecular mass = .28/24.3 = .0115
mass of O/molecular mass = .41/16 = .0256
so we have .0256 moles of O to .0115 moles of Mg
.0256/.0115 = 2.224
I suppose that could be Mg3O7 for a ratio of 2.3333etc
or perhaps Mg4O9 for a ratio of 2.25 (pretty close)
but I bet it is MgO2 for a ratio of 2 (the simple whole number they want is 2 :)
To calculate the moles of Mg and O, you need to use their respective masses and the molar mass of each element.
1. Moles of Mg:
Divide the mass of Mg (0.28 g) by the molar mass of Mg (24.31 g/mol):
moles of Mg = 0.28 g / 24.31 g/mol
2. Moles of O:
Divide the mass of O (0.41 g) by the molar mass of O (16.00 g/mol):
moles of O = 0.41 g / 16.00 g/mol
To find the simplest whole number ratio of the moles of Mg to O, divide both moles by the smaller value obtained in steps 1 and 2:
- Divide the moles of Mg by the smaller value.
- Divide the moles of O by the smaller value.
Next, round off the ratios to the nearest whole number.
Now, let's find the empirical formula:
The empirical formula represents the simplest whole number ratio of atoms in a compound.
For example, if the moles of Mg to mol of O are in a ratio of 1:2, the empirical formula could be MgO. However, let's use the ratios calculated to determine the empirical formula in this case.
Once you have the simplest whole number ratio, you can use it to write the empirical formula by placing the element symbols with their respective ratios.
Now, to determine the molecular formula, you need to know the molecular mass of the compound - magnesium oxide in this case.
The molecular mass of magnesium oxide is given as 40.3 g/mol.
To find the molecular formula from the empirical formula, divide the molecular mass by the empirical formula mass. If the result is a whole number, multiply the empirical formula by that whole number.
I will need the empirical formula mass to calculate the molecular formula. Could you please provide the empirical formula you obtained from the previous steps?
To calculate the moles of Mg and O, we need to use their respective molar masses. The molar mass of Mg is 24.31 g/mol, and the molar mass of O is 16.00 g/mol.
First, let's calculate the moles of Mg:
Moles of Mg = Mass of Mg / Molar mass of Mg
Moles of Mg = 0.28 g / 24.31 g/mol
Moles of Mg ≈ 0.0115 mol
Next, let's calculate the moles of O:
Moles of O = Mass of O / Molar mass of O
Moles of O = 0.41 g / 16.00 g/mol
Moles of O ≈ 0.0256 mol
To find the simplest whole number ratio of moles of Mg to moles of O, we divide both values by the smallest value (0.0115 mol in this case):
Moles of Mg / Moles of O ≈ 0.0115 mol / 0.0115 mol ≈ 1
Moles of O / Moles of O ≈ 0.0256 mol / 0.0115 mol ≈ 2
The closest whole number ratio is approximately 1:2. Therefore, the empirical formula is MgO.
To find the molecular formula, we need the molecular mass of magnesium oxide, which is given as 40.3 g/mol.
To calculate the empirical formula mass:
Empirical formula mass = (Molar mass of Mg) + (Molar mass of O)
Empirical formula mass = 24.31 g/mol + 16.00 g/mol
Empirical formula mass ≈ 40.31 g/mol
Next, we divide the molecular mass by the empirical formula mass to find the ratio:
Molecular mass / Empirical formula mass = 40.3 g/mol / 40.31 g/mol
Molecular mass / Empirical formula mass ≈ 1
Since the ratio is approximately 1, the molecular formula is the same as the empirical formula, which is MgO.