Lesson 12 What happens when substances are mixed

Lesson 12 What happens when substances are mixed with water?

Concepts Solutions are mixtures of a solution and a solvent Solubility and insolubility are properties of matter. Properties of solutions include uniform composition and transparency

Objectives Observe the process of dissolving Identify the characteristics of a solution Observe that substances can be classified as soluble or insoluble in water Discuss and define some terms that relate to solution

Notes Solutions are homogeneous mixtures of two or more substances The substance present in the larger proportion in a solution is the solvent The substance in the smaller proportion is the solute

Many liquids and gases will dissolve in water Ex. Oxygen is dissolved in water. Sulfur Dioxide can dissolve in rainwater to form acid rain Air can be considered a solution of gases with nitrogen as the solvent and other gases like oxygen and carbon dioxide as the solutes

Solids can also form solutions. Metals can be mixed to form alloys which are considered to be solutions Solutions in which water is the solvent are called aqueous solutions When a solvent dissolves a solute , the particles of the solute disperse throughout the solvent

Aqueous solutions can be divided into two groups Electrolytes – solutions that can conduct electricity And Non-electrolytes – Solutions that do not conduct electricity

Water is a polar molecule. This means it has a different charge at each end. Misconceptions Corrected Solutes do not appear when they dissolve The solute does not become water and the dissolved solute and solvent are not a single substance

Dissolving and melting are not the same thing Solutions can not be separated by filtration Addition of a solute does add volume to a solution; however the sum of the volume is less than the sum of the volume of the separate solute and solvent