To find the mass of Na2SO4 (sodium sulfate), you typically determine the molar mass of the compound first, and then you can use that, along with the number of moles you have, to calculate the mass. Here's how:
1. Determine the Molar Mass of Na2SO4:
The molar mass is the sum of the atomic masses of each element in the compound, multiplied by the number of times that element appears in the formula.
- Sodium (Na): The atomic mass of sodium is approximately 22.99 grams/mole. Since there are two sodium atoms in Na2SO4, their total contribution is 2 * 22.99 = 45.98 g/mol.
- Sulfur (S): The atomic mass of sulfur is approximately 32.07 grams/mole. There is only one sulfur atom, so its contribution is 32.07 g/mol.
- Oxygen (O): The atomic mass of oxygen is approximately 16.00 grams/mole. There are four oxygen atoms, so their total contribution is 4 * 16.00 = 64.00 g/mol.
Calculation:
Molar Mass of Na2SO4 = (2 Atomic mass of Na) + (1 Atomic mass of S) + (4 Atomic mass of O)
Molar Mass of Na2SO4 = (2 22.99) + (32.07) + (4 * 16.00)
Molar Mass of Na2SO4 = 45.98 + 32.07 + 64.00
Molar Mass of Na2SO4 = 142.05 g/mol
2. Calculate the Mass Using the Number of Moles:
If you know the number of moles (n) of Na2SO4, you can calculate the mass (m) using the following formula:
m = n M*
Where:
- m = mass (in grams)
- n = number of moles
- M = molar mass (in g/mol)
Example:
Let's say you have 0.5 moles of Na2SO4. To find the mass:
Mass = 0.5 moles * 142.05 g/mol
Mass = 71.025 grams
Therefore, 0.5 moles of Na2SO4 has a mass of approximately 71.025 grams.
In summary, you determine the mass of Na2SO4 by first calculating its molar mass (approximately 142.05 g/mol) and then multiplying the number of moles you have by this molar mass.
