A story of homogeneous mixtures, their properties and characteristics. Solutions A story of homogeneous mixtures, their properties and characteristics.

Solutions We are going to look at the characteristics of how sugar dissolves in some water. This is a typical solution.

SUGAR WATER SOLUTION Individual sugar molecules break apart from the solid and enter the solution. Actual molecules can NOT be seen, we will use the dots to represent dissolved sugar molecules.

Characteristics of solutions: Uniform concentration throughout. Don’t settle out. Clear and transparent, could be colored. Consists of a single phase. Pass through filters because of tiny particles.

Solute dissolved in solvent The solvent does the dissolving and is in the great quantity. The solute is dissolved and is in the lesser quantity. In this example, sugar is the solute and water is the solvent.

TYPES OF SOLUTIONS: Gas dissolved in a gas. Gas dissolved in a liquid. Air is a good example, it is a mixture of nitrogen, oxygen and other gases. Gas dissolved in a liquid. Carbonated beverages are good examples, carbon dioxide gas dissolved in water. Liquid dissolved in a liquid. The antifreeze in your car’s radiator is a mixture of ethylene glycol and water.

TYPES OF SOLUTIONS: Solid dissolved in a liquid. Aqueous solution. There are many examples, such as saline solution is a salt dissolved in water. Aqueous solution. Any solution that has water as the solvent.

RATE OF SOLUTION The rate of solution is how fast the solute will dissolve in the solvent. We will discuss four factors that affect the rate of solution: Temperature Surface Area Pressure Motion

What makes the solute dissolve faster? Temperature: The higher the temperature, the faster the particles move. Therefore they can dissolve faster. Surface Area: The greater the surface area, the finer the particles are. This allows more contact between the solvent and solute; hence a faster solution.

What makes the solute dissolve faster? Pressure: Only affects gases, but they will dissolve faster if the pressure is higher. Motion: Stirring or shaking will cause the particles to come in contact with the solvent quicker, therefore the rate of solution increases.

How much is dissolved? Unsaturated: The solvent can dissolve more solute. Saturated: The solvent has dissolved as much solute as it can at the temperature. Supersaturated: More solute is dissolved in the solvent than possible. This is done by heating a solution and then letting it cool. This only works for certain chemicals.

How much is dissolved? Dilute: Not much solute dissolved in the solvent. Concentrated: A lot of solute is dissolved in the solvent. Dilute and concentrated are relative terms, not exact amounts.

Questions: Can a dilute solution be saturated? Yes. Some chemicals do not dissolve very much so they may become saturated with very little solute. Can a concentrated solution be unsaturated? Yes, concentrated is just a relative term, more solute might be able to be dissolved even a lot has dissolved

Turn the worksheet over and run the Solubility Curve program.