Solutions

 Describe the properties of a solution.  Identify the solute and solvent in the preparation of a solution.  Describe and give examples of various types of solutions.  Differentiate between solution terms.

Pure substances – substances in which all particles have the same properties. Mixtures - contains more than one kind of particle.

Heterogeneous mixtures  not evenly distributed.  individual particles are usually distinguishable. Sand and water Salt and pepper  Sometimes called suspensions.  Use filters to separate suspension components. Heterogeneous mixtures will often settle out if left to stand.

Heterogeneous mixtures can occur between two or more liquids. Emulsion - a suspension of liquids. If we let emulsions sit, they will eventually separate too.

Can look homogenous: Blood, milk, mayonnaise, whip cream, jelly… Colloids / Gels Not easily filtered and do not settle out. Groups of large molecules suspended in mixture. Are usually opaque or translucent Light scatters off particles and does not pass through mixture – Tyndall Effect

Homogeneous mixtures  particles of are evenly distributed.  cannot be easily separated. Salt or sugar dissolved in water  Usually called solutions.  Solutions do NOT settle out if left to stand.  Solutions cannot be easily filtered. SOLUTION - a homogeneous mixture of two or more substances where all substances are distributed as individual molecules or ions.

A solution is made up of one or more solutes and a solvent. Solvent - is the substance that does the dissolving. Solute - is the dissolved substance. If a mixture of same states, the solvent is the substance present in the larger amount. Solutions which have water as the solvent are known as aqueous solutions.

The terms soluble and insoluble are relative terms. If a substance does not dissolve in a solvent, that substance is said to be insoluble. If a substance is able to dissolve in a solvent, we call the substance soluble. soluble insoluble solute

All mixtures of gases are solutions. All gases mix to form homogeneous mixtures. When two liquids dissolve in each other, like alcohol and water, we say the liquids are miscible. When they do not dissolve, like oil and water, we say they are immiscible.

Solutions of metals are called alloys. Metals are mixed to take advantage of their individual properties - malleability, density, strength and resistance to oxidation (rusting). Steel - iron and carbon (stronger) Brass - copper and zinc (stronger) Bronze - copper and tin (stronger) Stainless steel - steel with chromium (resists rust) Gold - gold and copper (harder)

Mixtures suspension insoluble solution (homogeneous) solidliquid soluble (heterogeneous) (dissolve) emulsion immiscible miscible liquid solution (homogeneous) (heterogeneous) (dissolve) alloy (homogeneous) solid soluble (dissolve) solution (homogeneous) gas soluble (dissolve)

octane (l) ethanol (l) Ca(NO 3 ) 2 (s) ethanol (l) Ionic calcium nitrate is soluble in polar ethanol – this is a homogeneous solution. Nonpolar octane is immiscible in polar ethanol – this is a heterogeneous emulsion.

Key Words pure substancesmixtures suspensionssolute insolubleheterogeneous solution emulsion solublemiscible immisciblealloys homogeneous solvent ColloidTyndall Effect