Question

A quantity of NaCl was dissolved in 100 cm of solution to obtain

0.5M NaCl solution. Calculate the mass of NaCl used [Na=23.0 ,
CI=35.5]
​

Answer 1

2.93g

Explanation:first, let us calculate the number of mole of NaCl present in the solution. This is illustrated below:

Molarity = 0.5M

Volume = 100cm^3 = 100/1000 = 0.1L

Mole =?

Molarity = mole /Volume

Mole = Molarity x Volume

Mole of NaCl = 0.5 x 0.1 = 0.05mole

Now we can obtain the mass of NaCl as follows:

Molar Mass of NaCl = 23 + 35.5 = 58.5g/mol

Mole of NaCl = 0.05mol

Mass of NaCl =?

Mass = number of mole x molar Mass

Mass of NaCl = 0.05 x 58.5

Mass of NaCl = 2.93g