CHAPTER 19. QUANTITATIVE ASPECTS OF CHEMICAL CHANGE 19.3
For this equation, the units for volume are dm^3 (which is equal to litres). Therefore, the
unit of concentration is mol·dm−^3.
DEFINITION: Concentration
Concentration is a measure of the amount of solute that is dissolved in a
given volume of liquid. It is measured in mol·dm−^3.Example 12: Concentration Calculations 1
QUESTION
If 3 , 5 g of sodium hydroxide (NaOH) is dissolved in 2 , 5 dm^3 of water, what is the
concentration of the solution in mol·dm−^3?SOLUTION
Step 1:Find the number of moles of sodium hydroxiden=mM=^3 ,^5 g
40 , 01 g·mol−^1= 0, 0875 molStep 2:Calculate the concentrationC=Vn=^0 ,^0875 mol
2 , 5 dm^3= 0, 035 mol·dm−^3The concentration of the solution is 0 , 035 mol·dm−^3.Chemistry: Chemical change 351