Was the Wicked Witch a good chemistry student?

Did she correctly and scientifically describe

her demise?

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Question of the Day

Day 3 2-25

How can we predict the solubility of a salt based on its ions?

Electrolytes and Nonelectrolytes•Your cells use electrolytes, such as sodium and potassium ions, to carry electrical impulses across themselves and to other cells.

• An electrolyte imbalance can occur if you become dehydrated.

• When you exercise, you can lose water and electrolytes from your body through perspiration.

A. Metathesis reactions can also be called _______ ______________ reactions.

B.The mixing of 2 solutions will result in a chemical reaction if _____ are _________ from the solution.

double replacement

ions removed

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Metathesis (Exchange) Reactions

• Metathesis comes from a Greek word that means “to transpose.”

AgNO3 (aq) + KCl (aq) AgCl (s) + KNO3 (aq)

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Metathesis (Exchange) Reactions

• Metathesis comes from a Greek word that means “to transpose.”

• It appears the ions in the reactant compounds exchange, or transpose, ions.

AgNO3 (aq) + KCl (aq) AgCl (s) + KNO3 (aq)

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Solution Chemistry

• It is helpful to pay attention to exactly what species are present in a reaction mixture (i.e., solid, liquid, gas, aqueous solution).

• If we are to understand reactivity, we must be aware of just what is changing during the course of a reaction.

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Ions can be removed from solution by any of 3 processes:

1. The formation of an __________ solid, known as a _____________

2. The formation of either a weak

____________ or a ________________

3. The formation of a ____ that bubbles

out of the solution

insolubleprecipitate

electrolyte nonelectrolyte

gas

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Precipitation Reactions

When one mixes ions that form compounds that are insoluble (as could be predicted by the solubility guidelines), a precipitate is formed.

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C. ExamplesWrite the molecular, complete, and net ionic equations

for these reactions that occur in water.

1. Magnesium nitrate and sodium hydroxide

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C. ExamplesWrite the molecular, complete, and net ionic equations for

these reactions that occur in water.

2. Magnesium hydroxide and hydrochloric acid

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Postlabs due Wednesday 2-26.

Lab Reports and Presentations due Monday 3-3.

Day 2 2-24

Postlabs due Thursday 2-27.

Lab Reports and Presentations due Monday 3-3.

Day 2 2-24

1. What volume of 10 M HCl must be diluted to prepare 500 mL of 1 M HCl?

2. Barium hydroxide has a low solubility, but is considered a strong electrolyte. Explain how this is possible.

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Question of the Day

Day 4 2-26

How can we predict the solubility of a salt based on its ions?

C. ExamplesWrite the molecular, complete, and net ionic equations

for these reactions that occur in water.

3. Chromium(II) acetate and nitric acid

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C. ExamplesWrite the molecular, complete, and net ionic equations

for these reactions that occur in water.

4. Barium nitrate and sulfuric acid

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AssignmentsSolubility Rules Handout

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Double Pd 1 2-1Prepare 150 ml of 0.1M solutions of:

BaCl2

CaCl2

SrCl2

LiCl

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AssignmentsSolubility Rules Handout

Solution Formation

•What factors affect how fast a substance dissolves?

• Which dissolves faster sugar cubes or granulated sugar?• Why the stirring?• Sugar dissolves faster in hot / iced tea?

Solution Formation

Solution FormationThe compositions of the solvent and the solute determine whether or not a substance will dissolve.

•Factors that affect how fast a substance

dissolves include:

• Agitation

• Temperature

• Particle size of the solute

Like Dissolves Like

Solution Formation• AgitationAgitation (stirring or shaking) affects only the rate at which a solid solute dissolves.• It does not influence the

amount of solute that will dissolve.

• Agitation increases the rate of dissolving

Solution Formation

•Higher temperatures lead to an increased rate of dissolving.

Temperature

•At higher temperatures, the kinetic energy of molecules is greater than at lower temperatures, so the molecules move (and mix) faster.

Solution Formation• Particle Size of the Solute

Smaller particles expose a greater surface area and so increase rate of dissolving.• The more surface area of

the solute that is exposed, the faster the rate of dissolving.

•Which of the following will not speed up the rate at which a solid solute dissolves?

• A. Increasing the temperature

• B. Stirring the mixture

• C. Crushing the solute

• D. Decreasing the temperature

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Quick DrawMolarity

Net ionic equation

Solute

Dissociating

Diprotic acids

Spectator ions

VcMc=VdMd

electrolyte

Strong acids

mols/L

salts

Weak base

QUICK TALKNH3

Disperse

Strong base

Hydrogen bonding

Solute

Molecular equation

Molarity

Weak acid

Solvent

Tincture

VcMc = VdMd

Monoprotic

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