Solutions Solubility Solubility Rules

Water Most common solvent A polar molecule O  - a hydrogen bond H  +

Hydrogen Bonds Attract Polar Water Molecules

Solute and Solvent Solutions are homogeneous mixtures of two or more substances Solute The substance in the lesser amount Solvent The substance in the greater amount

Nature of Solutes in Solutions Spread evenly throughout the solution Cannot be separated by filtration Can be separated by evaporation Not visible, solution appears transparent May give a color to the solution

Types of Solutions air O 2 gas and N 2 gas gas/gas soda CO 2 gas in water gas/liquid seawater NaCl in water solid/liquid brass copper and zinc solid/solid (alloy)

Solute and Solvent Identify the solute and the solvent. A. brass: 20 g zinc + 50 g copper solute= 1) zinc 2) copper solvent = 1) zinc 2) copper B. 100 g H 2 O + 5 g KCl solute = 1) KCl 2) H 2 O solvent = 1) KCl 2) H 2 O

Solution A. brass: 20 g zinc + 50 g copper solute= 1) zinc solvent = 2) copper B. 100 g H 2 O + 5 g KCl solute = 1) KCl solvent = 2) H 2 O

Identifying Solutes Identify the solute in each of the following solutions: A. 2 g sugar (1) mL water (2) B mL ethyl alcohol(1) and 30.0 mL of methyl alcohol (2) C mL water (1) and 1.50 g NaCl (2) D. Air: 200 mL O 2 (1) mL N 2 (2)

Solution Identify the solute in each of the following solutions: A. 2 g sugar (1) B mL of methyl alcohol (2) C. 50 g NaCl (2) D. 200 mL O 2 (1)

“Like dissolves like” A ____________ solvent such as water is needed to dissolve polar solutes such as sugar and ionic solutes such as NaCl. A ___________solvent such as hexane (C 6 H 14 ) is needed to dissolve nonpolar solutes such as oil or grease.

Saturated and Unsaturated A saturated solution contains the maximum amount of solute that can dissolve. Undissolved solute remains. An unsaturated solution does not contain all the solute that could dissolve

Unsaturated or Saturated? At 40  C, the solubility of KBr is 80 g/100 g H 2 O. Indicate if the following solutions are (1) saturated or (2) unsaturated A. ___60 g KBr in 100 g of water at 40  C B. ___200 g KBr in 200 g of water at 40  C C. ___25 KBr in 50 g of water at 40  C

Solution At 40  C, the solubility of KBr is 80 g/100 g H 2 O. Indicate if the following solutions are (1) saturated or (2) unsaturated A. 2 Less than 80 g/100 g H 2 O B. 1 Same as 100 g KBr in 100 g of water at 40  C, which is greater than its solubility C. 2 Same as 60 g KBr in 100 g of water, which is less than its solubility

Is it soluble? Which of the following solutes will dissolve in water? Why? 1) Na 2 SO 4 2) gasoline 3) I 2 4) HCl

Solution Which of the following solutes will dissolve in water? Why? 1) Na 2 SO 4 Yes, polar (ionic) 2) gasoline No, nonnpolar 3) I 2 No, nonpolar 4) HClYes, Polar

Solubility The maximum amount of solute that can dissolve in a specific amount of solvent usually 100 g. g of solute 100 g water

Temperature and Solubility of Solids TemperatureSolubility (g/100 g H 2 O) KCl(s)NaNO 3 (s) 0° °C °C °C The solubility of most solids (decreases or increases ) with an increase in the temperature.

Temperature and Solubility of Solids TemperatureSolubility (g/100 g H 2 O) KCl(s)NaNO 3 (s) 0° °C °C °C The solubility of most solids increases with an increase in the temperature.

Temperature and Solubility of Gases TemperatureSolubility(g/100 g H 2 O) CO 2 (g)O 2 (g) 0°C °C °C The solubility of gases (decreases or increases) with an increase in temperature.

Temperature and Solubility of Gases TemperatureSolubility(g/100 g H 2 O) CO 2 (g)O 2 (g) 0°C °C °C The solubility of gases decreases with an increase in temperature.

Solubility of Gases A. Why would a bottle of carbonated drink possibly burst (explode) when it is left out in the hot sun ? B. Why would fish die in water that gets too warm?

Solubility curves

Summary