Question

How many moles of NaCl are contained in 0.1 L of a 0.20 M solution?

Answer 1

Remember that M=mol/liter. We can use this concentration to find the number of moles in 0.1L of solution:

$0.1L\cdot\frac{0.20mol}{L}=0.02mol$

There are 0.02 moles of NaCl.