Question

Calculate the molarity and molality of a 10 g/L NaCl solution

Answer 1

0,171 M NaCl and 0,168 m NaCl

Step-by-step explanation:

Molarity (M) is an unit of chemical concentration that relates moles of solute per liters of solution and molality (m) is another unit of chemical concentration that relates moles of solute per kg of solution.

For a solution of 10g/L of NaCl the molarity is:

10g/L NaCl×
`(1mol)/(58,44 g)` = 0,17 moles/L of NaCl≡ 0,171 M NaCl

For molality you can know that in 1 L you have 0,17 moles of NaCl.

The kg of solution are:

0,010 kg of NaCl (solute) + 1 kg of solvent (Water, 1L of water is 1 kg) = 1,01 kg of solution.

Thus, molality of 10 g/L NaCl solution is:

`(0.17 moles)/(1,01 kg)` = 0,168 m NaCl

I hope it helps!