What are we doing Today? Review Day Homework Questions Review In class questions & homework

HW Check 1) P.173-174  Numbers 21-25

Magnetic Field Direction The north pole of a compass points in the direction of the magnetic field. This direction is always away from a north magnetic pole and toward a south magnetic pole.

Solubility & Concentration

Concentration of Solution Solvent Solute

Concentration of Solution Molarity Parts ratio % m/V , m/m , V/V Moles of solute Liter of solution Mol L (C) = = amount of solute (g or ml) amount of solution (g or ml) = (102) or (106) or (109)

Molarity Example Problem 1 NaCl 12.6 g of NaCl are dissolved in water making 344mL of solution. Calculate the molar concentration. C = n / V C = concentration n = solute (mol) V = Volume (L)

Molarity Example Problem 2 NaCl How many moles of NaCl are contained in 250.mL of solution with a concentration of 1.25 M? C = n / V Volume x concentration = moles solute

Molarity Example Problem 3 NaCl What volume of solution will contain 15 g of NaCl if the solution concentration is 0.75 M? C = n / V moles solute ÷ concentration = volume solution

Mass and volume units must match. % Concentration % (w/w) = % (w/v) = % (v/v) = Mass and volume units must match. (g & mL) or (Kg & L)

% Concentration Example Problem 1 Example Problem 2 (Solid in a Liquid) What is the concentration in %w/v of a solution containing 39.2 g of potassium nitrate in 177 mL of solution? % (w/v) = Example Problem 2 (Liquid in a Liquid) What is the concentration in %v/v of a solution containing 3.2 L of ethanol in 6.5 L of solution? % (v/v) =

What volume of 1.85 %w/v solution is needed to % Concentration Example Problem 3 What volume of 1.85 %w/v solution is needed to provide 5.7 g of solute? % (w/v) = We know: We want to get: g solute ÷ concentration = volume solution

Parts per million/billion (ppm & ppb) or = ppm or = ppb AND For very low concentrations: = ppt parts per trillion Mass and volume units must match. (g & mL) or (Kg & L)

ppm & ppb or Example Problem 1 An Olympic sized swimming pool contains 2,500,000 L of water. If 1 tsp of salt (NaCl) is dissolved in the pool, what is the concentration in ppm? 1 teaspoon = 6.75 g NaCl or

ppm & ppb or Example Problem 2 An Olympic sized swimming pool contains 2,500,000 L of water. If 1 tsp of salt (NaCl) is dissolved in the pool, what is the concentration in ppb? 1 teaspoon = 6.75 g NaCl or