How many grams of NaCl must be dissolved in 500 g of H₂O to prepare a 0.750 m solution?
Molar Mass(NaCl) = 58.44 g/mol

Question

How many grams of NaCl must be dissolved in 500 g of H₂O to prepare a 0.750 m solution? Molar Mass(NaCl) = 58.44 g/mol

Quizplus · Accepted Answer

First we need to calculate the number of moles of NaCl needed to prepare the solution:

0.750 mol/L = 0.750 moles / 1 L

Since we have 500 g (0.5 kg) of solution, we need to calculate the number of moles of solute (NaCl) that would be present in this amount of solution:

molarity = moles of solute / volume of solution (in L)

0.750 mol/L = moles of NaCl / 0.5 L

moles of NaCl = 0.750 mol/L × 0.5 L = 0.375 moles

Finally, we can calculate the mass of NaCl needed:

mass = moles × molar mass

mass = 0.375 moles × 58.44 g/mol = 21.9 g NaCl

Therefore, the answer is C. 21.9 g NaCl.

How Many Grams of NaCl Must Be Dissolved in 500