Solutions and Dissolving Rates

When you see the word solution what do you think of? Page 35

Essential Question

• Generalize the three main factors that effect dissolving rates.

What’s in water?

Collected from underground source.Faucet Water –From city sourceContains minerals, sodium fluoride, chlorine, etc…

Carbonated Water – Contains dissolved carbon dioxide evenly distributed through the liquid.

Distilled Water -Most minerals removed by distillationPurified further by reverse osmosis and deionization

A homogeneous mixture of two or more substances evenly distributed at the molecular level

Cannot be filtered

exists in every phase of matter.

Metal solutions are called alloys.

Solutions

Solvent – does the dissolving. Is present in the greatest amount.

Solute – gets dissolved.

When particles are evenly spread out, the solute has dissolved.

Parts of a solution

Stirring

Crushing

Shaking

Increased Temperatures

Increasing solubility

Understanding dissolving rates has made taking medicine easier and safer.Time capsules and microencapsulation:

How does

that work?

Smaller doses of medicine are more effective (steadier supply to body over time).

Safer (less side effects) and more convenient.

More cost-effective.

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Equilibrium ( or saturation point)

As many solute molecules are dissolving as are coming back out of solution

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SolubilityWhen a solute will dissolve in a specific amount of solvent under certain conditions.

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3 things Solubility depends on:

Chemical nature of solventTemperature of the solutionVolume of the solvent

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Chemical Nature

Insoluble

Some solutes are more soluble in a solvent than others

If a substance does not dissolve in a solvent.

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TemperatureSolubility of a solid in a liquid increases with increasing temperature– (Give example)– (Give relationship)

Solubility of a gas in a liquid increases with decreasing temperature.– (give example)– (give relationship)

Everyday ExampleWarm sodas fizz more than cold sodas when

you open them because CO2 gas is less soluble

at higher temperatures

Solubility of a gas DECREASES as

Temperature INCREASES

Solubility of a solid INCREASESas

Temperature INCREASES

Everyday ExampleWhen making tea, does sugar dissolves faster if the water is hot or cold?

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Temperature-Solubility Graph for Salts

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Solubility of Gases:

Depends on Pressure and Temperature.

Solubility of a gas in a liquid increases with increasing pressure.

Everyday ExampleOpening a bottle of soda decreases the pressure inside the bottle. This

decreases the solubility of CO2 in the soda and results in the formation

of bubbles, or fizz.

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How much is Dissolved?– Saturated

– Unsaturated

– Supersaturated

No more solute will dissolve; full.

More solute can be dissolved; not full

More solute is dissolved than is normally possible; unstable

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To supersaturate a solution:

Add solute until solution is saturatedThen heat and add more soluteCool down to normal temperature.

Remember…you should write 5

things you learned in complete sentences.

Summarize!!!!!

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Remember…you should write 5

things you learned in complete sentences.

Summarize!!!!!

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Remember…you should write 5

things you learned in complete sentences.

Summarize!!!!!

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