Chapter 81 Solutions and Their Concentrations Chapter 8

2 Section 8.1: Types of Solutions

Chapter 83 Solution - A homogeneous mixture is composed of a solute and a solvent.

Chapter 84 The Solution Process Solute – The substance which is dissolved. Solvent – The substance which acts as the dissolving medium.

Chapter 85 A Common Everyday Example Solute – The substance which is dissolved. Solvent – The substance which acts as the dissolving medium. Kool -Aid Powder (solute) Water (solvent)

6 Remember back… Pure substances have fixed compositions. Example: H 2 O, you cannot change the ratio of H to O in water without producing a whole new substance. Solutions however have variable composition! Variable Composition - Different ratios of solute to solvent are possible.

Chapter 87 Variable Composition - Different ratios of solute to solvent are possible. of coffee!

8 Types of Solutions Original State of Solute Solvent Examples gas Air, natural gas gasliquidCarbonated drinks gassolidHydrogen in Platinum liquidgasWater vapour in air liquid Alcohol in water liquidsolidAmalgams, Mercury in silver solidgasMothballs in air solidliquidSugar (or salt) in water solid Alloys, Cu-Ni coins

Aqueous Solutions – A solution in which water is the solvent (does the dissolving). 9

10 Factors Affecting Solubility Miscible liquids - Liquids that readily dissolve in each other.Mix in any proportions. Immiscible liquids – Liquids that do not readily dissolve in each other --do not mix. Solute-Solvent Interactions Ex: Water and alcohol Ex: Vinegar in oil and diesel and water

Chapter 811Alloys Alloys – Solid solutions of metals –when combining 2 or more metals together to enhance properties. i.e bronze = tin + copper

Chapter 812 Solubility and Saturation Solubility – of a solute is the amount of solute that dissolves in a given quantity of solvent, at a certain temperature. Solubility of NaCl= 36 g in 100 mL of water at 20 °C

Chapter 813 Saturated Solutions and Solubility Unsaturated (Dilute) Solution – A solution in which additional solute may be dissolved. Saturated Solution – A solution in which no more solute may be dissolved. Supersaturated Solution – A solution that contains more of the dissolved solute than could be dissolved by the solvent under normal circumstances.

Chapter 814

Soluble or Insoluble that is the Question? Chapter 815 Soluble – Means that a solute has a solubility of 1 g per 100 mL of solvent. Insoluble- Means that the solubility of the solute is 0.1 g per 100 mL of solvent. Sparingly (slightly) Soluble – substances between these two limits.

Chapter 816 We can use the concept of intermolecular forces to explain the characteristics of solutes and solvents when forming solutions. So why do some solutes dissolve in solvents while others do not? The answer is POLARITY!! 1. Dipole-Dipole 2. London Forces 3. Hydrogen Bonding Solute-Solvent Interactions

Chapter 817 Draw the Lewis Structures for the following: A. H 2 O B. NH 3 C. CH 4 D. CO 2 E. NaCl F. CH 2 O G. MgO H. CH 3 CH 2 OH Which of these molecules Would dissolve in water? Question?

Pauling EN Scale Chapter 8 18

Chapter 819 Factors Affecting Solubility “Like Dissolves Like” -Polar molecules will dissolve in polar solvents. -Non-polar molecules will dissolve in non-polar solvents. Solute-Solvent Interactions

Chapter 820 Factors Affecting Solubility -Solubility of a solid in a liquid increases with temperature. -The higher the temperature, the greater the solubility. -Solubility of another liquid in a liquid is not greatly affected by temperature. -Solubility of a gas in a liquid decreases with temperature. -The higher the temperature, the less soluble the gas. Temperature Effects

Chapter 821 Ways of Expressing Concentration

Chapter 822 Ways of Expressing Concentration Molar Concentration