Final answer:
To find how many grams of lithium oxide are needed to make a 225.0 mL of a 1.2 M solution, calculate the number of moles needed using the molarity formula, then convert moles to grams using the molar mass of lithium oxide. None of the provided answer choices match the calculated value of 8.07 grams.
Step-by-step explanation:
To calculate how many grams of lithium oxide (Li₂O) are required to make 225.0 mL of a 1.2 M solution, we need to use the molarity formula and the molar mass of lithium oxide. Molarity (M) is defined as moles of solute per liter of solution. The molarity formula is M = moles/L. The molar mass of Li₂O, which is the sum of the molar masses of 2 Li atoms (6.94 g/mol each) and 1 O atom (16.00 g/mol), equals 29.88 g/mol.
First, we calculate the number of moles needed:
1.2 moles/L * 0.225 L = 0.27 moles
Then, convert moles to grams:
0.27 moles * 29.88 g/mol = 8.07 grams
So, to prepare a 1.2 M solution of lithium oxide in 225.0 mL of water, 8.07 grams would be required. This means the correct answer is not listed among the provided options (A, B, C, or D).