Question

Calculate the mass (in g) of solute needed to prepare a solution with the given concentration and volume.

Sea water has a concentration of approximately 0.60 M sodium chloride. How much
sodium chloride is dissolved in 1.00 L of solution?
Coke has a concentration of 0.342 M. What mass of sugar (in g) is dissolved in a 2-L
bottle of coke?
What volume of concentrated nitric acid (15.8 M) is needed to prepare 4.0 L of a 2.0 M solution?
What volume of 9.0 M copper (II) sulfate stock solution is needed to prepare 3.0 L of a 5.0 M
solution?

Answer 1

1. 35g NaCl.

2. 234g sugar.

3. 0.506L of concentrated nitric acid are needed.

4. 1.67L of 9.0M copper (II) sulfate are needed

Step-by-step explanation:

Molarity is defined as the ratio between moles of solute and the volume of the solution.

1. 1.00L * (0.60mol / L) = 0.60 moles NaCl are dissolved

To convert moles to mass we must use its molar mass:

0.60mol NaCl * (58.44g/mol) =

35g NaCl

2. 2L * (0.342mol / L) = 0.684 moles Sugar = moles sucrose

0.684 mol * (342.30g / mol) = 234g sugar

3. 4L of a 2.0M are:

4L * (2.0mol/L) = 8moles

8mol * (1L / 15.8mol) = 0.506L of concentrated nitric acid are needed

4. 3.0L * (5.0 mol / L) = 15.0 moles copper (II) sulfate.

15.0mol * (1L / 9.0mol) = 1.67L of 9.0M copper (II) sulfate are needed