Chapter 7 Solutions 7.1 Solutions

Solutions: Solute and Solvent are homogeneous mixtures of two or more substances form when there is sufficient attraction between solute and solvent molecules have two components: the solvent, present in a much larger amount, and the solute, present in a smaller amount

Solutes Solutes spread evenly throughout the solution cannot be separated by filtration can be separated by evaporation are not visible, but can give a color to the solution A solution of copper(II) sulfate (CuSO4) forms as particles of solute dissolve and become evenly dispersed among the solvent (water) molecules.

Types of Solutes and Solvents Solutes and solvents may be solids, liquids, or gases.

Water as a Solvent Water is one of the most common solvents in nature is a polar molecule due to polar O–H bonds molecules form hydrogen bonds important in many biological compounds

Solutions with Ionic and Polar Solutes NaCl crystals undergo hydration as water molecules surround each ion and pull it into solution. solid separate ions

Solutions with Nonpolar Solutes Nonpolar solutes require nonpolar solvents to form a solution.

“Like Dissolves Like” “Like dissolves like”: polarity of solute and solvent must be similar to form a solution.

Learning Check Identify the solute in each of the following solutions. A. 2 g of sugar and 100 mL of water B. 60.0 mL of ethyl alcohol and 30.0 mL of methyl alcohol C. 55.0 mL of water and 1.50 g of NaCl D. Air: 200 mL of O2 and 800 mL of N2

Solution Identify the solute in each of the following solutions. A. 2 g of sugar and 100 mL of water The solute is sugar. B. 60.0 mL of ethyl alcohol and 30.0 mL of methyl alcohol The solute is methyl alcohol. C. 55.0 mL of water and 1.50 g of NaCl The solute is NaCl. D. Air: 200 mL of O2 and 800 mL of N2 The solute is O2.

Learning Check Solid LiCl is added to water. It dissolves because A. the Li+ ions are attracted to the 1) oxygen atom ( −) of water 2) hydrogen atom ( +) of water B. the Cl− ions are attracted to the

Solution Solid LiCl is added to water. It dissolves because A. the Li+ ions are attracted to the 1) oxygen atom (−) of water B. the Cl− ions are attracted to the 2) hydrogen atom ( +) of water

Learning Check Which of the following solutes will dissolve in water? Why? A. Na2SO4 B. gasoline (nonpolar) C. I2 D. HCl

Solution Which of the following solutes will dissolve in water? Why? A. Na2SO4 will dissolve, ionic B. gasoline (nonpolar) will not dissolve, nonpolar C. I2 will not dissolve, nonpolar D. HCl will dissolve, polar Most polar and ionic solutes dissolve in water because water is a polar solvent. Nonpolar solutes will not dissolve in water.