Question

What is the molarity of a Ca(NO₃)₂ solution when 100g is dissolved in 750 ml?

A) 0.813 M
B) 2.19 M
C) 0.13 M
D) 0.002 M
E) 0.342 M

Answer 1

The molarity of a Ca(NO3)2 solution when 100g is dissolved in 750 ml is approximately 0.813 M, by dividing the number of moles of solute by the volume of the solution in liters.

Step-by-step explanation:

To calculate the molarity of a Ca(NO3)2 solution, we first need to find its molar mass. Calcium nitrate has a molar mass of 164.08 g/mol (as determined in Example 10.3.1). Next, we'll convert the mass of calcium nitrate to moles:

100 g ÷ 164.08 g/mol = 0.6093 moles of Ca(NO3)2

Then, we convert the volume from milliliters to liters:

750 mL = 0.75 L

Now, we can calculate molarity, which is moles of solute per liter of solution:

0.6093 moles ÷ 0.75 L = 0.8124 M

Thus, the molarity of the Ca(NO3)2 solution is approximately 0.812 M, which rounds to 0.813 M, matching option A).