How many grams of sodium sulfate na2so4 must be added to make 500ml of a 12.5 M sodium sulfate solution
To find out how many grams of sodium sulfate (Na2SO4) must be added to make a 500ml of a 12.5 M sodium sulfate solution, you need to follow these steps:
Step 1: Calculate the number of moles of Na2SO4 needed.
To do this, you can use the equation:
Molarity (M) = Moles (mol) / Volume (L)
Rearranging the equation to solve for moles gives:
Moles (mol) = Molarity (M) * Volume (L)
Given that the molarity (M) is 12.5 M and the volume (V) is 0.5 L (since 500 ml is equal to 0.5 L), you can substitute these values into the equation:
Moles (mol) = 12.5 M * 0.5 L
Moles (mol) = 6.25 mol
Therefore, you need 6.25 moles of Na2SO4.
Step 2: Convert moles to grams.
To convert moles to grams, you need to know the molar mass of Na2SO4. The molar mass can be calculated by adding up the atomic masses of the elements present in the compound:
Na (sodium) = 22.99 g/mol
S (sulfur) = 32.07 g/mol
O (oxygen) = 16.00 g/mol (there are 4 oxygen atoms in Na2SO4)
Molar mass of Na2SO4 = (22.99 g/mol * 2 Na) + (32.07 g/mol * 1 S) + (16.00 g/mol * 4 O)
Molar mass of Na2SO4 = 46.00 g/mol + 32.07 g/mol + 64.00 g/mol
Molar mass of Na2SO4 = 142.07 g/mol
Now you can calculate the mass of Na2SO4 needed by multiplying the number of moles calculated in Step 1 by the molar mass:
Mass (g) = Moles (mol) * Molar mass (g/mol)
Mass (g) = 6.25 mol * 142.07 g/mol
Mass (g) = 889.19 g (rounded to the nearest hundredth)
Therefore, you need approximately 889.19 grams of Na2SO4 to make 500ml of a 12.5 M sodium sulfate solution.
How many mols do you want? That's mols = M x L = ?
Then mols = grams/molar mass. You know molar mass and mols, solve for grams.