Molarity What is it and how is it calculated?

Molarity What is it? A measurement of a solution’s concentration How much solute is dissolved in a solvent Moles of solute per Liter of solvent mol / L = M

Molarity How is it calculated? Moles ÷ Liter o g  mol o mL  L

Representative Particles Moles A Mass (grams) 1 mol______ 6.02 X particles 1 mol atomic/molar mass from periodic table 1 mol _____1 mol_____ atomic/molar mass from periodic table Moles B Mol B Mol A Mol B Molarity ÷ L x L

Mole  Molarity # of moles x 1 = M L g Cr(NO 3 ) 2 x 1 mol Cr(NO 3 ) 2 = 2.56 x mol 176 g Cr(NO 3 ) 2 Cr(NO 3 ) 2 Example: Calculate the molarity if g of Cr(NO 3 ) 2 is dissolved in 500 mL of water. 500 mL x 1 L =.5 L 10 3 mL

Mole  Molarity 2.56 x mol x 1 = 5 x M Cr(NO 3 ) 2.5 L

Mole  Molarity # of moles x 1 = M L Example: Calculate the molarity if 6.75 g of Na 3 PO 4 is dissolved in 1000 mL of water. 4 x M Na 3 PO 4

Molarity  Mole M x L = # of moles.25 L x 3.0 mol AlCl 3 = 0.75 mol AlCl 3 L Example: Calculate the mass of AlCl 3 that was dissolved in 250 mL of water to make a 3.0 M solution. 250 mL x 1 L =.25 L 10 3 mL

Molarity  Mole 0.75 mol AlCl 3 x 132 g AlCl 3 = 99 g AlCl 3 1 mol AlCl 3

Molarity  Mole M x L = # of moles Example: Calculate the mass of (NH 4 ) 2 SO 4 that was dissolved in 750 mL of water to make a 2.5 M solution. 250 g (NH 4 ) 2 SO 4