Concentration Molarity Parts per Million Percent by Mass Percent by Volume

Molarity What is the molarity of a 500.0 mL solution of NaOH (FM = 40.0) with 60.0 g of NaOH (aq)? Convert g to moles and mL to L first! M = moles / L = 1.50 moles / 0.5000 L = 3.00 M How many grams of NaOH does it take to make 2.0 L of a 0.100 M solution of NaOH (aq)? Moles = M X L = 0.100 M X 2.0 L = 0.200 moles Convert moles to grams: 0.200 moles X 40.0 g/mol = 8.00 g

Parts Per Million 100.0 grams of water is evaporated and analyzed for lead. 0.00010 grams of lead ions are found. What is the concentration of the lead, in parts per million? ppm = (0.00010 g) / (100.0 g) X 1 000 000 = 1.0 ppm If the legal limit for lead in the water is 3.0 ppm, then the water sample is within the legal limits (it’s OK!)

Percent by Mass A 50.0 gram sample of a solution is evaporated and found to contain 0.100 grams of sodium chloride. What is the percent by mass of sodium chloride in the solution? % Comp = (0.100 g) / (50.0 g) X 100 = 0.200%

Percent By Volume Substitute “volume” for “mass” in the above equation. What is the percent by volume of hexane if 20.0 mL of hexane are dissolved in benzene to a total volume of 80.0 mL? % Comp = (20.0 mL) / (80.0 mL) X100 = 25.0%

Colligative Properties Vapor Pressure Lowering B.P. Elevation DTf= m. kf (or D Tb= m. kb) F.P. Depression Osmotic Pressure Colligative properties depend upon # of particles (ions, atoms, molecule= particle) Which will have lowest B.P. 1M NaCl, 1 M C6H12O6 or 1M Na3PO4?

Neutralization 10.0 mL of 0.20 M HCl is neutralized by 40.0 mL of NaOH. What is the concentration of the NaOH? #H MaVa = #OH MbVb, so Mb = #H MaVa / #OH Vb = (1)(0.20 M)(10.0 mL) / (1) (40.0 mL) = 0.050 M How many mL of 2.00 M H2SO4 are needed to completely neutralize 30.0 mL of 0.500 M KOH?

Formulas, Naming and Properties of Acids Arrhenius Definition of Acids: molecules that dissolve in water to produce H3O+ (hydronium) as the only positively charged ion in solution. HCl (g) + H2O (l)  H3O+ (aq) + Cl- Properties of Acids Naming of Acids Formula Writing of Acids

Properties of Acids Acids react with metals above H2 on Table J to form H2(g) and a salt. Acids have a pH of less than 7. Dilute solutions of acids taste sour. Acids turn phenolphthalein CLEAR, litmus RED and bromthymol blue YELLOW. Acids neutralize bases. Acids are formed when acid anhydrides (NO2, SO2, CO2) react with water for form acids. This is how acid rain forms from auto and industrial emissions.

Naming of Acids (polyatomic ion) -ate +ic acid Binary Acids (H+ and a nonmetal) hydro (nonmetal) -ide + ic acid HCl (aq) = hydrochloric acid Ternary Acids (H+ and a polyatomic ion) (polyatomic ion) -ate +ic acid HNO3 (aq) = nitric acid (polyatomic ion) -ide +ic acid HCN (aq) = cyanic acid (polyatomic ion) -ite +ous acid HNO2 (aq) = nitrous acid

Formula Writing of Acids Acids formulas get written like any other. Write the H+1 first, then figure out what the negative ion is based on the name. Cancel out the charges to write the formula. Don’t forget the (aq) after it…it’s only an acid if it’s in water! Hydrosulfuric acid: H+1 and S-2 = H2S (aq) Carbonic acid: H+1 and CO3-2 = H2CO3 (aq) Chlorous acid: H+1 and ClO2-1 = HClO2 (aq) Hydrobromic acid: H+1 and Br-1 = HBr (aq) Hydronitric acid: Hypochlorous acid: Perchloric acid:

Formulas, Naming and Properties of Bases Arrhenius Definition of Bases: ionic compounds that dissolve in water to produce OH- (hydroxide) as the only negatively charged ion in solution. NaOH (s)  Na+1 (aq) + OH-1 (aq) Properties of Bases Naming of Bases Formula Writing of Bases

Properties of Bases Bases react with fats to form soap and glycerol. This process is called saponification. Bases have a pH of more than 7. Dilute solutions of bases taste bitter. Bases turn phenolphthalein PINK, litmus BLUE and bromthymol blue BLUE. Bases neutralize acids. Bases are formed when alkali metals or alkaline earth metals react with water. The words “alkali” and “alkaline” mean “basic”, as opposed to “acidic”.

Naming of Bases Bases are named like any ionic compound, the name of the metal ion first (with a Roman numeral if necessary) followed by “hydroxide”. Fe(OH)2 (aq) = iron (II) hydroxide Fe(OH)3 (aq) = iron (III) hydroxide Al(OH)3 (aq) = aluminum hydroxide NH3 (aq) is the same thing as NH4OH: NH3 + H2O  NH4OH Also called ammonium hydroxide.

Formula Writing of Bases Formula writing of bases is the same as for any ionic formula writing. The charges of the ions have to cancel out. Calcium hydroxide = Ca+2 and OH-1 = Ca(OH)2 (aq) Potassium hydroxide = K+1 and OH-1 = KOH (aq) Lead (II) hydroxide = Pb+2 and OH-1 = Pb(OH)2 (aq) Lead (IV) hydroxide = Pb+4 and OH-1 = Pb(OH)4 (aq) Lithium hydroxide = Copper (II) hydroxide = Magnesium hydroxide =