Chemistry 3.2

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ChemistryChapter 3 - Section 2

Solubility

Wednesday, July 11, 2012

Water – The Universal Solvent

Wednesday, July 11, 2012

Water – The Universal Solvent

•Many solutions have water as the solvent.

Wednesday, July 11, 2012

Water – The Universal Solvent

•Many solutions have water as the solvent. •These solutions are called an aqueous solution.

Wednesday, July 11, 2012

Water – The Universal Solvent

•Many solutions have water as the solvent. •These solutions are called an aqueous solution. •Water dissolves many solutes and so scientists call it the universal solvent.

Wednesday, July 11, 2012

Water – The Universal Solvent

•Many solutions have water as the solvent. •These solutions are called an aqueous solution. •Water dissolves many solutes and so scientists call it the universal solvent. •Why is water such a great solvent? Let’s find out.

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Molecular Compounds - Sharing is Caring

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Molecular Compounds – Polar or Nonpolar

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Ionic Bonding

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How Water Dissolves Ionic Compounds

Wednesday, July 11, 2012

How Water Dissolves Ionic Compounds

Wednesday, July 11, 2012

How Water Dissolves Ionic Compounds

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How Water Dissolves Ionic Compounds

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How Water Dissolves Molecular Compounds

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Dissolving Molecular Compounds

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What will dissolve? The spoon

or the sugar??

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Like Dissolves Like

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Like Dissolves

Like

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Like Dissolves

Like•Polar solvents will dissolve polar solutes.

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Like Dissolves

Like•Polar solvents will dissolve polar solutes.

•Nonpolar solvents will dissolve nonpolar solutes.

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Like Dissolves

Like•Polar solvents will dissolve polar solutes.

•Nonpolar solvents will dissolve nonpolar solutes.

•Polar will not dissolves nonpolar and vice versa.

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Like Dissolves

Like•Polar solvents will dissolve polar solutes.

•Nonpolar solvents will dissolve nonpolar solutes.

•Polar will not dissolves nonpolar and vice versa.

•Think about oil and water. Is the oil polar or nonpolar?

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How Much Will Dissolve?

Wednesday, July 11, 2012

How Much Will Dissolve?

Wednesday, July 11, 2012

How Much Will Dissolve?

•If you tried to dissolve a lot of sugar in a small glass of water, not all of the sugar would dissolve.

Wednesday, July 11, 2012

How Much Will Dissolve?

•If you tried to dissolve a lot of sugar in a small glass of water, not all of the sugar would dissolve.

•Solubility is the measurement of how much solute dissolves in a given amount of solvent.

Wednesday, July 11, 2012

How Much Will Dissolve?

•If you tried to dissolve a lot of sugar in a small glass of water, not all of the sugar would dissolve.

•Solubility is the measurement of how much solute dissolves in a given amount of solvent.

•Solubility is usually describes as how much can dissolve in 100g of solvent at a given temperature.

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Solubility in a

Liquid-Solid Solution

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Solubility in a

Liquid-Solid SolutionTemperature is included here because the solubility of a

solute changes as the temperature of

the solvent changes.

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Solubility in a

Liquid-Solid Solution

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Solubility in a

Liquid-Solid Solution

As you heat water, you can

dissolve sugar in water faster rate, but also more

sugar will dissolve.

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Solubility in a

Liquid-Gas Solution

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Solubility in a

Liquid-Gas Solution

In a liquid-gas solution, the opposite is true.

Wednesday, July 11, 2012

Solubility in a

Liquid-Gas Solution

In a liquid-gas solution, the opposite is true.

As the temperature increases, the solubility

decreases.

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Solubility in a

Liquid-Gas Solution

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Solubility in a

Liquid-Gas Solution

This is because the water molecules will be moving faster at higher temperatures. This movement will bump the gas out of

the solution, therefore decreases solubility.

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Saturated Solutions

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Saturated Solutions•If you add calcium carbonate to 100g of water at 25˚C, only 0.0014g will dissolve. No more can dissolve.

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Saturated Solutions•If you add calcium carbonate to 100g of water at 25˚C, only 0.0014g will dissolve. No more can dissolve. •This solution is called a saturated solution.

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Saturated Solutions•If you add calcium carbonate to 100g of water at 25˚C, only 0.0014g will dissolve. No more can dissolve. •This solution is called a saturated solution. •If the solution was a liquid-solid solution, the extra solid would settle on the bottom of the container.

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Saturated Solutions

Wednesday, July 11, 2012

Saturated Solutions

•The solubility of sugar in 100g of water at 25˚C is 204g.

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Saturated Solutions

•The solubility of sugar in 100g of water at 25˚C is 204g. •If you had a solution with 50g of sugar in 100g of water, the solution is called unsaturated. More solute could dissolve.

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Saturated Solutions

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Saturated Solutions

•A hot solvent can usually hold more solute then a cooler one.

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Saturated Solutions

•A hot solvent can usually hold more solute then a cooler one. •If a saturated solution cools, some of the solute can fall out of the solution.

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Wednesday, July 11, 2012

Saturated Solutions

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Saturated Solutions

•A hot solvent can usually hold more solute then a cooler one.

Wednesday, July 11, 2012

Saturated Solutions

•A hot solvent can usually hold more solute then a cooler one. •If a saturated solution cools, some of the solute can fall out of the solution.

Wednesday, July 11, 2012

Saturated Solutions

•A hot solvent can usually hold more solute then a cooler one. •If a saturated solution cools, some of the solute can fall out of the solution.

•But if the solution is cooled slowly, sometimes the excess solute remains dissolved for a period of time. This solution is called supersaturated.

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Rate of Dissolving

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•Solubility does not tell you how fast a solute will dissolve.

Rate of Dissolving

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•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve.

Rate of Dissolving

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•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

Rate of Dissolving

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•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

✴it is stirred

Rate of Dissolving

Wednesday, July 11, 2012

•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

✴it is stirred✴it is shaken

Rate of Dissolving

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•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

✴it is stirred✴it is shaken✴the temperature is increased

Rate of Dissolving

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•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

✴it is stirred✴it is shaken✴the temperature is increased

•How exactly do these factors help?

Rate of Dissolving

Wednesday, July 11, 2012

•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

✴it is stirred✴it is shaken✴the temperature is increased

•How exactly do these factors help? ✴They increase the rate at which the surfaces of the solute come into contact with the solvent.

Rate of Dissolving

Wednesday, July 11, 2012

•Solubility does not tell you how fast a solute will dissolve. •Some solutes will dissolve quickly, others take a long time to dissolve. •A solution dissolves faster when:

✴it is stirred✴it is shaken✴the temperature is increased

•How exactly do these factors help? ✴They increase the rate at which the surfaces of the solute come into contact with the solvent.✴Increasing the area of contact between the solute and the solvent can also increase the rate of dissolving

Rate of Dissolving

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Concentrated!

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Concentrated!•The concentration of a solution tells you how much solute is present compared to the amount of solvent.

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Concentrated!•The concentration of a solution tells you how much solute is present compared to the amount of solvent. •When you are comparing the concentrations of two solutions with the same type of solute and solvent, you can use a simple description such as: dilute or concentrated.

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Concentrated!

•The Dead Sea is 5+ times saltier than Earth's oceans. As water evaporates, salt is left behind. When the saturation point is reached, the salt forms these pillars.

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Measuring Concentrations

•One way to give the concentration is by using the percentage of the volume of the solution that is made up of the solute.

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Effects on Solute Particles•Solute particles affect the physical properties of the solvent, such as the boiling point or the freezing point.

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Effects on Solute Particles•Adding a solute, such as NaCl, changes the way the water molecules can arrange themselves. The solute gets in the way.

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Effects on Solute Particles•To overcome this interference of the solute, a lower temperature is needed for the solvent to freeze.

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Effects on Solute Particles

•When a solvent begins to boil, the solvent molecules are gaining enough energy to move from the liquid state to the gaseous state.

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Effects on Solute Particles

•When a solute is introduced, its particles interfere with the evaporation of the solvent particles.

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Effects on Solute Particles

•For water and NaCl, the NaCl will block the H2O from escaping the liquid and becoming a gas.

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Effects on Solute Particles

•More energy is needed for the solvent particles to escape from the liquid, and the boiling point of the solution will be higher.

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Finished!

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