Question

A chemist prepares a solution by adding 448 mg of Co(NO3)2 (MW = 182.94 g/mol ) to a volumetric flask, and then adding water until the total volume of the contents of the flask reaches the calibration line that indicates 500 mL . Determine the molarity of the prepared solution.

Answer 1

Molarity of solution is 0.0049 M

Step-by-step explanation:

Molarity of a solution is the ratio of number of moles of solute to volume of solution in Liter

Number of moles is the ratio of mass to molecular weight of a compound.

Here
`Co(NO_(3))_(2)` is the solute.

448 mg of
`Co(NO_(3))_(2)` = 0.448 g of
`Co(NO_(3))_(2)`

So, 0.448 g of
`Co(NO_(3))_(2)` =
`(0.448)/(182.94)` moles of
`Co(NO_(3))_(2)` = 0.00245 moles of
`Co(NO_(3))_(2)`

Total volume of solution = 500 mL = 0.5 L

So, molarity of solution =
`(0.00245)/(0.5)M=0.0049 M`