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Lecture 4.2 – The Dissolving Process and the Rate of Dissolving. A Problem. Cools down to room temperature. Gross! . Justify – TPS. Why does this solid appear at cold temperatures, but it wasnt present when the cider was hot?.
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Lecture 4.2 – The Dissolving Process and the Rate of Dissolving
A Problem Cools down to room temperature Gross!
Justify – TPS • Why does this solid appear at cold temperatures, but it wasntpresent when the cider was hot?
How does temperature, pressure, and surface area impact rate of dissolving?
I. Dissolving • We can alter the rate at which the solute dissolves by: 1. Changing the temperature 2. Changing the surface area of the solute 3. Changing the pressure of the solution.
II. Temperature and Dissolving • As you increase the temperature, molecules start moving faster. • By moving faster, the molecules are better able to grab the solute, form the cages around them and pull them into the solution. • Therefore, the faster molecules are moving, the faster something dissolves.
Temperature and Dissolving Rate Cold liquid Hot liquid
III. Surface Area and Dissolving • As you increase the surface area, the rate at which the solute dissolves increases. • As you increase the surface area of a substance, you are providing more sites for the solvent to interact with the solute.
Justify – TPS • Why does your soda become carbonated when you open it? What is happening?
IV. Pressure and Dissolving • As you increase the pressure, the rate at which the solute dissolves increases. • The solubility and pressure relationship is clearly seen when a gas dissolves in a liquid. • Gases can dissolve into liquids.
IV. Pressure and Dissolving • When a gas is above a liquid and the pressure is increased, the gas molecules collide more often with the wall of the liquid and this causes more gas to be pushed into the liquid.