Concentration  A measure of how much solute is dispersed throughout the solvent  Molarity (M), molality (m), and mole fraction ( χ ), mass percent

Concentration  90.0 g of glucose (C 6 H 12 O 6 ) is dissolved in 250 mL H 2 O. Calculate (a) molality, (b) mass percent, and (c) mole fraction of the resulting solution. 2.0 m, 26.0 %,  300 mL of aqueous solution contains 84.5 g of sodium acetate. If the density of the solution is g/mL, calculate the (a) molarity, (b) molality, (c) mass percent, and (d) mole fraction of sodium acetate M, 4.25 m, 25.8 %, 0.071

Dilultions  Dilution is the process of decreasing concentration of a solute, usually by adding more solvent  The key to any dilution is that the number of moles of solute doesn’t change … M 1 V 1 =n,M 2 V 2 =n  If 150 mL of water are added to 250 mL of a 3.0 M solution of HCl, what is the solution’s final concentration? 1.9 M

Stoichiometry  Concentration can be used as another conversion factor  How many mL of 2.0 M HCl must be added to 4.2 g of magnesium for all the magnesium to react? 173 mL