24.40 grams of Anhydrous sodium sulfate will absorb 30.946 grams of water.
First, calculate the molar mass of Anhydrous sodium sulfate by looking up the molar mass of each element in it.
Sodium = 22.989769
Sulfur = 32.065
Oxygen = 15.999
Sum the product of each element count by their molar mass
2 * 22.989769 + 32.065 + 4 * 15.999 = 142.0405
So 1 mole of Anhydrous sodium sulfate masses 142.0405 grams
Calculate how many moles you have.
24.40 g / 142.0405 g/mole = 0.171782 mole
Calculate the molar mass of H2O
Hydrogen = 1.00794
2 * 1.00794 + 15.999 = 18.01488
Each mole of Anhydrous sodium sulfate can absorb 10 moles of H2O, so
0.171782 moles * 10 * 18.01488 g / mole = 30.946 grams
