Final answer:
To calculate the molarity of the solution formed by dissolving 21.0 g of barium carbonate (BaCO3) in 800.0 mL of water, the number of moles of BaCO3 is found first and then divided by the volume of the solution in liters, yielding a molarity of 0.133 M.
Step-by-step explanation:
To determine the molarity of the resulting solution after dissolving 21.0 g of barium carbonate (BaCO3) in 800.0 mL of solvent, we first need to calculate the number of moles of BaCO3 using its molecular weight. The molecular weight of BaCO3 is (137.327 + 12.011 + 3×16.000) g/mol = 197.338 g/mol. Now, we can calculate the moles:
moles of BaCO3 = 21.0 g / 197.338 g/mol = 0.1064 moles
Since the volume of the solution is 800.0 mL, which is equivalent to 0.800 L, we can calculate the molarity (M) of the solution as:
M = moles/volume (in liters) = 0.1064 moles / 0.800 L = 0.133 M
Therefore, the molarity of the BaCO3 solution is 0.133 M.