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Solutions and Concentrations. Notes Page 5. SOLUTIONS . A homogenous mixture of two or more substances. 2 PARTS OF A SOLUTION. SOLUTE A solute is the dissolved substance in a solution. Sugar in soda Carbon dioxide in soda Salt in salt water SOLVENT
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Solutions and Concentrations Notes Page 5
SOLUTIONS A homogenous mixture of two or more substances
2 PARTS OF A SOLUTION • SOLUTE • A solute is the dissolved substance in a solution. Sugar in soda Carbon dioxide in soda Salt in salt water • SOLVENT • A solvent is the dissolving medium in a solution. • Water in salt water Waterin soda
Molarity = concentration • Amount of substance (mol) • Volume of mixture (L) • Unit = mol/L or M • 1.0 M = 1 molar • 12.0 M = 12 molar
Example 1 • 1.5 mol of NaCl are dissolved in 1 L of water. What is the molarity of the solution? • 1.5 molNaCl= 1.5 mol/L or 1.5 M • 1 L H2O
Example 2 • 100 g of NaCl are dissolved in 1 L of water. What is the molarity of the solution? • 100 g NaCl|1 molNaCl= 1.71 mol 58.44 g NaCl • 1.71 molNaCl= 1.71 M 1 L
Example 3 • 100 g of NaCl are dissolved in 250 mL of water. What is the molarity of the solution? • 100 g NaCl |1 molNaCl= 1.71mol • 58.44 g NaCl • 250 mL / 103 mL = 0.25 L • 1.71 molNaCl= 6.84 M 0.25 L
Example 4 • How many moles of NaCl are in 500 mL of a 0.25 M solution? • Basic formula: M = mol L • Convert: 500 mL = 0.5 L • 0.25 M = mol = 0.5 L x 0.25 M = mol 0.5 L = 0.125 molNaCl
Example 5 • How many grams of NaClare in 500 mL of a 2.25 M solution? • Basic formula: M = mol L • Convert: 500 mL = 0.5 L • 2.25 M = mol = 0.5 L x 2.25 M = mol 0.5 L= 1.125 molNaCl • 1.125 molNaCl| 58.44 g NaCl= 65.75 g NaCl 1 mol