J.R. S. answered 02/26/20
Ph.D. University Professor with 10+ years Tutoring Experience
As in your previous question, we have 0.130 M CaCl2 which mean 0.130 moles CaCl2 per liter of solution.
Since we want to make 3.40 L of solution, we calculate total moles of CaCl2 needed:
*** 3.40 L x 0.130 mo/L = 0.442 moles CaCl2 needed.
Next, we convert this to grams using the molar mass of CaCl2:
*** 0.442 moles CaCl2 x 110.98 g/mol = 49.1 g CaCl2 needed (to 3 significant figures)