A sample of 76 g of NaCl is dissolved to make 1 L of solution. What is the molarity of the solution? Show your work.

The answer is 1.3 mol of NaCl.

We know that there is 76 g of NaCl in 1L of the solution.

But we need to calculate the molarity.

First, we will need the molar mass of NaCl, which is the sum of relative atomic masses of Na (22.99 g/mol) and Cl (35.45 g/mol):

Mr (NaCl) = A (Na) + A (Cl) = 22.99 g/mol + 35.45 g/mol = 58.44 g/mol.

This says that there are 58.44 g of NaCl in 1 mole. So, in how many moles will be 76 g of NaCl) ? Use the proportion:

58.44 g : 1 mol = 76 g : x

After crossing the products:

x * 58.44 g = 1 mol * 76 g

x = 76 / 58.44 mol = 1.3 mol