Question

A solution of table salt contains 2 moles of NaCl in 500mL of water. What is the concentration?

How many grams of NaCl are in 0.5L of 4.0M solution?

Answer 1

concentration is typically given in M (moles/L). 500 mL of water is 500/1000L, or 0.5L. so divide 2moles/0.5L to get the concentration in moles/L.

for the second question, 4.0M means 4.0 moles/L, so multiply 4.0M * 0.5L to get moles of NaCl, and from there, multiply by the molar mass of NaCl to get grams.

Answer 2

2/0.5=4mol/litre