Imagine a hot Imagine a hot summer day. summer day. You’ve been You’ve been outdoors and outdoors and you are really you are really thirsty. A tall, thirsty. A tall, cool glass of cool glass of water would water would taste great.taste great.Or would it?Or would it?

Have you ever tasted distilled Have you ever tasted distilled water from the supermarket?water from the supermarket?

It tastes flat.It tastes flat. It is “just plain water”It is “just plain water”To make it you boil tap water so it To make it you boil tap water so it

becomes a gas. Then you collect the becomes a gas. Then you collect the liquidliquid

It separates the water from the It separates the water from the dissolved materials that give it dissolved materials that give it flavor.flavor.

Tap water Tap water

A mixture of pure water H2O and A mixture of pure water H2O and a variety of other substances, a variety of other substances, such as chlorine, fluoride, and such as chlorine, fluoride, and

metallic ions. Gases like carbon metallic ions. Gases like carbon dioxide are also dissolved in dioxide are also dissolved in

water.water.

Tap water is an example of a kind Tap water is an example of a kind of mixture called a solution.of mixture called a solution.

Acids, Bases, and Acids, Bases, and SolutionsSolutions

SuspensionSuspension

A mixture in which particles can be A mixture in which particles can be seen easily and separated by seen easily and separated by filtration or settling.filtration or settling.

Pepper and water make a suspensionPepper and water make a suspension

SolutionsSolutions

Homogeneous mixtures (well mixed) in Homogeneous mixtures (well mixed) in which parts are too small to be seen and which parts are too small to be seen and do not settle.do not settle.

Same properties throughoutSame properties throughout Can not be separated through filtering or Can not be separated through filtering or

settling. May use evaporation or boiling settling. May use evaporation or boiling away.away.

Salt water is an example.Salt water is an example.

ALL Solutions ALL Solutions

Consist of Consist of 2 parts:2 parts: Solvent: does the dissolving, present in Solvent: does the dissolving, present in

largest amount. largest amount. Solute: is dissolved, present in smaller Solute: is dissolved, present in smaller

amount.amount.

Examples of SolutionsExamples of Solutions

Soda is a solution ofcarbon dioxide, sugar,and flavorings dissolvedin water.

An alloy is a solidsolution of metals.

Water as a SolventWater as a Solvent

In many common solutions, the solvent is In many common solutions, the solvent is water. water.

Sugar in water, for example, is the starting Sugar in water, for example, is the starting solution for flavored soft drinks. Adding food solution for flavored soft drinks. Adding food coloring gives the drink its color. Dissolving coloring gives the drink its color. Dissolving carbon dioxide gas in the mixture produces carbon dioxide gas in the mixture produces soda.soda.

Because water dissolves in so many Because water dissolves in so many substances it is often called the substances it is often called the “UNIVERSAL SOLVENT”“UNIVERSAL SOLVENT”

Solutions Without WaterSolutions Without Water

Many solutions are made with solvents Many solutions are made with solvents other than waterother than water Gasoline is a solution of several different Gasoline is a solution of several different

liquid fuels. (C8H18)liquid fuels. (C8H18)

SOLUTIONS can be made of any combination SOLUTIONS can be made of any combination of gases, liquids, or solids.of gases, liquids, or solids.

Have you ever put a packet of Have you ever put a packet of powdered flavoring into a bottle powdered flavoring into a bottle

of water?of water?

What happened to the powder?What happened to the powder?

Particles in a solutionParticles in a solution

Why do solutes seem to disappear when Why do solutes seem to disappear when you mix them with water?you mix them with water?

If you had a microscope powerful enough If you had a microscope powerful enough to look at the particles in the mixture what to look at the particles in the mixture what would you see?would you see?

This is what happens!This is what happens!

Whenever a Whenever a solution forms, particles of the solution forms, particles of the solute leave each other and become solute leave each other and become surrounded by the particles of the solvent.surrounded by the particles of the solvent.

Conductivity and SolutionsConductivity and Solutions

Many ionic compounds are highly soluble Many ionic compounds are highly soluble and dissolve easily in water. and dissolve easily in water.

Water molecules attract the ions and pull Water molecules attract the ions and pull them away from each other.them away from each other.

The solution that forms when an ionic The solution that forms when an ionic compound dissolves in water can conduct compound dissolves in water can conduct an electrical current.an electrical current.

Happens Happens because the ions are charged and because the ions are charged and can move freely past each other.can move freely past each other.

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electricity-electricity-

ConcentrationConcentrationSuppose you make two cups of tea. You leave the first tea bag in the cup For 15 minutes. You put a second tea bag in a second cup for only a few minutes. When you are done, one cup of tea is darker than the other.

What is happening?

They differ in their They differ in their concentrationsconcentrations

They differ in the amount of solute (tea) They differ in the amount of solute (tea) dissolved in a certain amount of solvent dissolved in a certain amount of solvent (water). (water).

Dilute solution: A small amount of solute is Dilute solution: A small amount of solute is dissolved in the solvent.dissolved in the solvent.

Concentrated solution: A mixture that has Concentrated solution: A mixture that has a lot of solute dissolved in it. a lot of solute dissolved in it.

SolubilitySolubility

Solubility: A measure of how well a solute Solubility: A measure of how well a solute can dissolve at a given temperature.can dissolve at a given temperature.

If a substance dissolves in If a substance dissolves in water then, how well does it water then, how well does it

dissolve?”dissolve?” Suppose you add sugar to a glass of ice Suppose you add sugar to a glass of ice

tea. How much can you add?tea. How much can you add? You can add half a teaspoon to make it You can add half a teaspoon to make it

sweet.sweet. Or, you can add two teaspoons to make it Or, you can add two teaspoons to make it

really sweet.really sweet. IS THERE A LIMIT TO HOW “SWEET” IT IS THERE A LIMIT TO HOW “SWEET” IT

CAN BE???????CAN BE???????

YES!!!!YES!!!!

At the temperature of ice tea, three or four At the temperature of ice tea, three or four tea spoons are about all you can add. tea spoons are about all you can add.

No matter how much you stir the tea, no No matter how much you stir the tea, no more sugar will dissolve.more sugar will dissolve.

Saturated, unsaturated, or Saturated, unsaturated, or supersaturated?supersaturated?

solutions hold the maximum solutions hold the maximum amount of solute at a given temperatureamount of solute at a given temperature

solutions are not holding as solutions are not holding as much as possible at that temperaturemuch as possible at that temperature

solutions are holding solutions are holding more than they should be able to at the more than they should be able to at the given temperature.given temperature.

What increases the rate of What increases the rate of solution?solution?

Crushing the Crushing the solutesolute

Heating the Heating the solvent, if you are solvent, if you are dissolving a solid dissolving a solid in a liquidin a liquid

Stirring the Stirring the solutionsolution

Which holds more solute?Which holds more solute?

Warm liquid holds less dissolved gasWarm liquid holds less dissolved gas Warm liquid holds more dissolved solidWarm liquid holds more dissolved solid

This solution is saturated. It is holding all it can, and we can see some undisolved solute.

Changing SolubilityChanging Solubility

Which holds more sugar: iced tea or hot Which holds more sugar: iced tea or hot tea?tea?

• Ice tea quickly becomes saturatedIce tea quickly becomes saturated• Yet, hot tea can hold several more teaspoons of Yet, hot tea can hold several more teaspoons of

sugar!sugar!

FACTORS AFFECTING FACTORS AFFECTING SOLUBILITYSOLUBILITY

Temperature: Temperature: Solids: as temperature is increased, solubility Solids: as temperature is increased, solubility

increasesincreases Gases: Become less soluble when temp goes Gases: Become less soluble when temp goes

up. up. More carbon dioxide will dissolve in cold water than in More carbon dioxide will dissolve in cold water than in

hot water. If you open a warm bottle of soda, carbon hot water. If you open a warm bottle of soda, carbon dioxide escapes the liquid in greater amounts than if the dioxide escapes the liquid in greater amounts than if the water had been chilled.water had been chilled.

Why does warm soda taste “FLAT”? Because it contains Why does warm soda taste “FLAT”? Because it contains less gas!less gas!

Solubility in 100 g water at 0 Solubility in 100 g water at 0 degrees Cdegrees C

COMPOUND SOLUBILITY (g)

SALT NaCl 35.7

Baking Soda NaHCO3 6.9

Carbon Dioxide CO2 0.348

Sugar C12H22O11 180

Soda instantly freezes!Soda instantly freezes!

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Next FactorNext Factor

Solvents: Solvents: Have you ever shaken a bottle of salad Have you ever shaken a bottle of salad

dressing? Then you have seen how quickly dressing? Then you have seen how quickly water and oil separate.water and oil separate.

Why? Water is polar and oil is nonpolar.Why? Water is polar and oil is nonpolar. Polar and nonpolar compounds do not mix Polar and nonpolar compounds do not mix

well. well. Liquids: The solvent affects how well a solute Liquids: The solvent affects how well a solute

dissolves. dissolves.

LIKE DISSOLVES LIKELIKE DISSOLVES LIKE

Ionic and polar compounds dissolve in Ionic and polar compounds dissolve in polar solvents.polar solvents.

Nonpolar compounds do not dissolve in Nonpolar compounds do not dissolve in polar solventspolar solvents

• Example- PaintsExample- Paints Latex or water based paints can be cleaned up with just Latex or water based paints can be cleaned up with just

soap and watersoap and water Oil-based paints require cleanup with a nonpolar solvent, Oil-based paints require cleanup with a nonpolar solvent,

like turpentine.like turpentine.

Effects of solutes on solutionsEffects of solutes on solutions

Making ice cream!!!Making ice cream!!! First we mixed the milk, sugar and vanilla.First we mixed the milk, sugar and vanilla. Then we froze the mixture by using ice. Then we froze the mixture by using ice. To make it cold enough what did we add?To make it cold enough what did we add?

SALT!!! Why?SALT!!! Why?

Milk freezes at a temperature lower than Milk freezes at a temperature lower than the the freezing point of water (0 degrees C)freezing point of water (0 degrees C)

Adding salt to the ice created a mixture Adding salt to the ice created a mixture that was several degrees cooler, cold that was several degrees cooler, cold enough to freeze the ice cream!!enough to freeze the ice cream!!

Salt can affect boiling point too!Salt can affect boiling point too!

Have you ever added salt to a pot of water Have you ever added salt to a pot of water when you were trying to cook spaghetti?when you were trying to cook spaghetti?

Why?Why? Water boils at a temperature higher than Water boils at a temperature higher than

100 degrees C, the boiling point of water.100 degrees C, the boiling point of water. Adding two teaspoons of salt/ quart will raise Adding two teaspoons of salt/ quart will raise

the boiling point 1 degree C. the boiling point 1 degree C. This change is enough to cook the spaghetti This change is enough to cook the spaghetti

faster!faster!

Effects of solutes on SolutionsEffects of solutes on Solutions

Lowering freezing point: Solutes lower the Lowering freezing point: Solutes lower the freezing point of a solvent. freezing point of a solvent.

• Salt was the solute added to water when we made Salt was the solute added to water when we made ice cream.ice cream.

Higher boiling points: Solutes raise the Higher boiling points: Solutes raise the boiling point of a solvent.boiling point of a solvent.

• Salt added to water when boiling spaghettiSalt added to water when boiling spaghetti

ACIDS AND BASESACIDS AND BASES

Acid and Bases Magic

Click above for website linkClick above for website link

Acids and BasesAcids and Bases

Acids and bases are substances Acids and bases are substances with specific physical and with specific physical and chemical properties chemical properties

We can determine if substances We can determine if substances are acidic or basic by testing their are acidic or basic by testing their pH or by indicators.pH or by indicators.

What did you eat for breakfast What did you eat for breakfast today?today?

An apple? An orange? Fruit juice?An apple? An orange? Fruit juice?

If so, an acid was part of your meal.If so, an acid was part of your meal.

What is an Acid?What is an Acid?

Acids: Any compound that increases the Acids: Any compound that increases the number of hydronium ions, when dissolved number of hydronium ions, when dissolved in water.in water.

A substance that tastes sour, reacts with metals A substance that tastes sour, reacts with metals and carbonates, and turns litmus paper red. and carbonates, and turns litmus paper red.

Hydronium ions form when a hydrogen ion, Hydronium ions form when a hydrogen ion, H+, separates from an acid and bonds with a H+, separates from an acid and bonds with a water molecule, H2O, to form a Hydronium water molecule, H2O, to form a Hydronium ion H3O+ion H3O+

WHAT ARE SOME WHAT ARE SOME EXAMPLES OF ACIDS EXAMPLES OF ACIDS THAT YOU KNOW??THAT YOU KNOW??

Properties of AcidsProperties of Acids

Sour TasteSour TasteEver tasted a lemon? Ever tasted a lemon?

What did it taste like? Other foods like this?What did it taste like? Other foods like this?

Contain citric acidContain citric acid

Other fruits like cherries, tomato, and apples Other fruits like cherries, tomato, and apples also contain acidalso contain acid

Vinegar a solution of water and acetic acidVinegar a solution of water and acetic acid

NOTE: Chemists never taste chemicals in order NOTE: Chemists never taste chemicals in order to identify them. Even though acidic foods are to identify them. Even though acidic foods are safe to eat, chemicals in labs may not be!!safe to eat, chemicals in labs may not be!!

Acids change color in indicatorsAcids change color in indicators

Turns blue litmus paper redTurns blue litmus paper red

Bromthymol turns from blue to yellowBromthymol turns from blue to yellow

Destroy chemical properties of Destroy chemical properties of basesbases

This is called neutralizationThis is called neutralization

They cancel each other outThey cancel each other out

Conduct an electrical currentConduct an electrical current

A water solution of the given substance A water solution of the given substance will conduct an electric current. will conduct an electric current. Acids break apart in water and form ionsAcids break apart in water and form ions Ions make it possible to conduct an electrical Ions make it possible to conduct an electrical

current!current!

React with metalsReact with metalsUpon chemically reacting with an Upon chemically reacting with an activeactive metal, will produce metal, will produce hydrogen gas (Hhydrogen gas (H22).).

The key word, of course, is active. Some metals, like gold, silver or The key word, of course, is active. Some metals, like gold, silver or platinum, are rather unreactive and it takes rather extreme platinum, are rather unreactive and it takes rather extreme conditions to get these "unreactive" metals to react. conditions to get these "unreactive" metals to react.

Not so with the metals in this property. They include the alkali metals Not so with the metals in this property. They include the alkali metals (Group I, Li to Rb), the alkaline earth metals (Group II, Be to Ra), as (Group I, Li to Rb), the alkaline earth metals (Group II, Be to Ra), as well as zinc and aluminum. well as zinc and aluminum.

Just bring the acid and the metal together Just bring the acid and the metal together at anything close to room temperature and at anything close to room temperature and you get a reactionyou get a reaction

IndicatorsIndicators

Organic substances that change color in the Organic substances that change color in the presence of an acid or a base.presence of an acid or a base.

Red cabbage juice will change color in the presence Red cabbage juice will change color in the presence of acids or basesof acids or bases

More properties of acidsMore properties of acids

Contain hydrogenContain hydrogen

Ionize in water to produce positive Ionize in water to produce positive hydronium ions (Hhydronium ions (H33oo++))

React with active metalsReact with active metals

May be hazardousMay be hazardous

Proton donorsProton donors

USES OF ACIDSUSES OF ACIDS

Used in many areas of industry and in Used in many areas of industry and in homes.homes.

Citric acid & ascorbic acid (vitamin C)= are found in Citric acid & ascorbic acid (vitamin C)= are found in orange juice. Help give soda its sharp tasteorange juice. Help give soda its sharp taste

Hydrochloric acid= Hydrochloric acid= make metals make metals from their ores. from their ores. Separates metals from the materials in which they are Separates metals from the materials in which they are combined.combined.

Nitric acid= fertilizer, rubber and plasticNitric acid= fertilizer, rubber and plastic

Sulfuric acid= most widely used industrial chemical in the Sulfuric acid= most widely used industrial chemical in the worldworld Paper, paint, detergent, fertilizerPaper, paint, detergent, fertilizer

Common AcidsCommon Acids

BASEBASE

Any compound that increases the Any compound that increases the number of hydroxide ions, OH+, number of hydroxide ions, OH+,

when dissolved in water.when dissolved in water.

Properties of BasesProperties of Bases

Taste BitterTaste Bitter

Have you ever accidentally tasted soap?Have you ever accidentally tasted soap?

Then you have tasted a base.Then you have tasted a base.

NOTE: Never use taste a way to identify a NOTE: Never use taste a way to identify a substance that is an unknown chemical, this substance that is an unknown chemical, this can be very dangerous.can be very dangerous.

Slippery feelingSlippery feeling

Soap also has that slippery feeling.Soap also has that slippery feeling.

Why?Why? They dissolve the fatty acids and oils from your skin and this They dissolve the fatty acids and oils from your skin and this

cuts down on the friction between your fingers as you rub them cuts down on the friction between your fingers as you rub them together. together.

In essence, the base is making soap out of you. Yes, bases are In essence, the base is making soap out of you. Yes, bases are involved in the production of soap! In the early years of soap involved in the production of soap! In the early years of soap making, the soaps were very harsh on the skin and clothes due making, the soaps were very harsh on the skin and clothes due to the high base content. Even today, people with very sensitive to the high base content. Even today, people with very sensitive skin must sometimes use a non-soap based product for bathing. skin must sometimes use a non-soap based product for bathing.

Bases change color in Bases change color in indicatorsindicators

Change the color of litmus paper blueChange the color of litmus paper blue

Bromthymol blue turns blue Bromthymol blue turns blue in the in the presence of a base.presence of a base.

Destroy chemical properties of Destroy chemical properties of acidsacids

This is called neutralizationThis is called neutralization

They cancel each other outThey cancel each other out

Conduct an electrical currentConduct an electrical current

Why?Why? Increase the number of hydroxide ions, OH-, Increase the number of hydroxide ions, OH-,

in a solution.in a solution. This ion is a hydrogen atom and an oxygen This ion is a hydrogen atom and an oxygen

atom bonded together. This gives they atom bonded together. This gives they hydroxide ion a negative charge.hydroxide ion a negative charge.

USES OF BASESUSES OF BASES

Soap and paperSoap and paper

Oven cleanersOven cleaners

Products to unclog drainsProducts to unclog drains

Compounds used to make cement and Compounds used to make cement and plasterplaster

Household cleaners and fertilizersHousehold cleaners and fertilizers

AntacidsAntacids

More properties of basesMore properties of bases

Contain hydroxide ion (OHContain hydroxide ion (OH--))

Proton acceptorsProton acceptors

Can be poisonous and corrosiveCan be poisonous and corrosive

Common basesCommon bases

pH ScalepH Scale

pH = a value that is used to express the pH = a value that is used to express the acidity or bascity (alkalinity) of a systemacidity or bascity (alkalinity) of a system

Describes how acidic or basic a solution Describes how acidic or basic a solution is. is.

Measure of the hydronium ion Measure of the hydronium ion concentration in the solutionconcentration in the solution

How to read the pH scaleHow to read the pH scale

Scale ranges from 0-14Scale ranges from 0-14

7 is neutral, solution is neither acidic or 7 is neutral, solution is neither acidic or basic (pure water)basic (pure water)

Acids solutions have pH less than 7Acids solutions have pH less than 7

Bases have pH greater than 7Bases have pH greater than 7

Neutralization reactionNeutralization reaction

The reaction of an acid and a base to form a The reaction of an acid and a base to form a neutral solution of water and a salt.neutral solution of water and a salt. Salt= an ionic compound that forms when a Salt= an ionic compound that forms when a

metal atom replaces the hydrogen atom of an metal atom replaces the hydrogen atom of an acid.acid.

Uses = many industrial and home usesUses = many industrial and home usesSeason food, preserve food, make other compounds Season food, preserve food, make other compounds (lye, sodium hydroxide and baking soda)(lye, sodium hydroxide and baking soda)

REMEMBER THE ICE CREAM LAB???REMEMBER THE ICE CREAM LAB??? Decrease the freezing point of waterDecrease the freezing point of water

NeutralizationNeutralization

Acid + Base = Water + SaltAcid + Base = Water + Salt

Ex: Ex: HClHCl + NaOH + NaOH H H22O + NaClO + NaCl

pH < 7pH < 7

Turn Turn litmus litmus from from blue to blue to redred

Change phenolphtalein to colorless

ACIDSACIDS

pH > 7pH > 7

Turn Turn litmus litmus from from red to red to blueblue

Change phenolphtalein to pink

BASESBASES

It’s time for lab!