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$: Chapter 8 Solutions - PC\|MACimages.pcmac.org/.../Uploads/Forms/Chapter_9_and_10... · 1 Chapter 8 Solutions ... together to form a ... Ions that are created by Ionization and allow$
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Chapter 8 Solutions

Section 1: Solutions and Other MixturesSection 1: Solutions and Other MixturesSection 1: Solutions and Other MixturesSection 1: Solutions and Other Mixtures

• What is a heterogeneous mixture?

• What is a homogeneous mixture?

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•A heterogeneous mixture does not

have a fixed composition.

–Every spoonful will have a different

amount of each component

�Ex) fruit salad, dirt, granite

Heterogeneous MixturesHeterogeneous MixturesHeterogeneous MixturesHeterogeneous Mixtures

1) Suspensions

• A suspension has particles that settle out when the mixture is allowed to stand.

– Ex) orange juice with pulp

Types of Heterogeneous MixturesTypes of Heterogeneous MixturesTypes of Heterogeneous MixturesTypes of Heterogeneous Mixtures

• Particles can be filtered out with a paper filter.

• Particles can be evenly dispersed throughout a

liquid or gas.

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A mixture in which the particles are

dispersed throughout but are not

heavy enough to settle out.


2) Colloids

– Ex) latex paint,

gelatin, egg whites,

blood plasma,

whipped cream,

marshmallows, fog.

• A colloid in which liquids that usually do not mix are spread throughout each other.


3) Emulsion

Ex: Mayonnaise• Egg yolk, oil and vinegar

Not uniformCoated

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•Mixture looks uniform even because

the components are too small to be

seen.

Homogeneous MixturesHomogeneous MixturesHomogeneous MixturesHomogeneous Mixtures

• Example: Kool-Aid, tea,

• A solution is a homogeneous mixture throughout

which two or more substances are uniformly

dissolved.


Solution

Solute - substance being

dissolved

Solvent - present in greater

amount

Ex: salt

Ex: water

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•Two or more

liquids that blend

together to form a

solution.


Miscible

•Liquids that do

NOT blend or

mix to form

solutions


Immiscible

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Solutions are not always liquid!– Amalgam= mercury dissolved in solid silver. Used in tooth fillings


• Solids to solids.

• 2 or more metals.


Alloys

Example: Brass is an alloy of

copper and zinc

Example: Bronze is n alloy

of tin and copper

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• Why is water called universal

solvent?

• Why do substances dissolve?

Section 2: How Substances Dissolve

• Water is found in almost everything.

–2/3 of Earth’s surface is water.

Water: A Common SolventWater: A Common SolventWater: A Common SolventWater: A Common Solvent

The “Universal Solvent”

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• The structure of water helps it dissolve charged particles.


Water is a polarmolecule.

•The oxygen atom attracts shared electrons more strongly than the hydrogen atoms in a water molecule.

“Like dissolves like”

Polar -Polar moleculesEx: methanol and water.


Polar and nonpolar substances do not mix.

•Oil is nonpolar

•do not have separate positive and

negative areas

•Water is polar

•has separate positive and negative

areas.

Non-polar -non-polar Ex: gasoline and oil.

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What makes solutes

dissolve faster?

• Larger surface area

• small pieces dissolves faster

than the same substance in big

pieces

• Stirring or shaking

• Heat

• more collisions between

particles


Section 3: Solubillity and

Concentration

• What is solubility?

• What happens when you add more solute to a saturated solution?

• How do you describe how much of a solute is in a solution?

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• If you continue adding sugar to lemonade, eventually the point is reached when no more sugar dissolves and the excess granules sink to the bottom of the glass.

How much can dissolve?

•Solubility : is the

maximum amount of a solute that can be dissolved in a given amount of solvent at a given temperature.

Solubility in WaterSolubility in WaterSolubility in WaterSolubility in Water

Solubility varies with temperature

Soluble – anything that dissolves in another substance. Insoluble – anything that does not dissolve in another substance.

Insoluble Soluble


Ex: Salt is soluble in water.

Ex: Oil is insoluble in water.

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� Unsaturated� more solute can be dissolved in the

solvent� Saturated

� no more solute can be dissolved in the solvent at the current temperature

� Supersaturated� the temperature of the solution is

raised so more solute can be dissolved. When the temperature drops, the solution holds more solute than normally capable.

• Concentration: the quantity of solute dissolved

in a given quantity of solution.

– different concentrations, depending on how much

solute and solvent are present.


Dilute – weak solution “less” solute present

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SATURATED SOLUTION

no more solute dissolves

UNSATURATED SOLUTIONmore solute

dissolves

SUPERSATURATED SOLUTION

becomes unstable, crystals form

concentration


• Temperature and pressure affect the

solubility of gases.


When the pressure is released, the carbon

dioxide bubbles out.

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Chapter 9 Acids, Bases, and Salts

• What are the properties of acids?

• What are the properties of bases?

• How is pH related to the concentration of

hydronium ions and hydroxide ions in

solution?

Section 1: Acids, Bases, and pH

Acid and Base Clip

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Acids are substances which release

hydrogen ions (H+) when added to water.

A hydrogen ion (H+) combines with a

water molecule (H2O) to produce a

hydronium ion (H3O+)

H+ + H2O � H3O+

The more hydronium ions that are

produced, the stronger the acid.

AcidsAcidsAcidsAcids

Properties of Acids

• Sour taste.

• pH below 7

• Changes litmus paper from blue to red.

• Very corrosive to metals (meaning that they react with metals producing hydrogen gas)

• Acids react with bases to produce salts and water

AcidsAcidsAcidsAcids

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\

• What is a base?

– Any compound that increases the number of hydroxide ions (OH-)when dissolved in water.

Therefore, most bases have hydroxide in the name or formula.

BasesBasesBasesBases

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• Changes litmus paper from red to blue.

• Very corrosive

• Bases react with acids to produce salts and water

Properties of Bases

• Bitter taste.

• Feels slippery.

• pH above 7.

BasesBasesBasesBases

Why do bases feel slippery?

• Bases react with oils and fats on the skin.

Getting bases and bleaches on your

fingers literally turns the fat in your skin,

into soap, hence the slippery.

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• A substance that conducts electricity when

dissolved in water is an electrolyte.

• Strong acids are strong electrolytes.

• Strong bases are also strong electrolytes.

Ions that are created by Ionization and allow the conduction of electricity!

ElectrolyteElectrolyteElectrolyteElectrolyte

pH reflects how much of an

acid or a base a substance is.

pH ScalepH ScalepH ScalepH Scale

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1 2 3 4 5 6 7 8 9 10 11 12 13 14

Neutral

Acid Alkali

A pH of 7 is completely neutral

neither an acid nor a base.

A pH less than 7 is an acid. A pH greater than 7 is a base.


• Ranges from 0 to 14

• 7 is neutral

• Strongest acid is HCl (pH=0)

• Strongest base is NaOH (Drano) (pH=14)


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• The strength of an acid and base depends on the distance it is away from 7.

–The closer to 0 and closer to 14 are the strongest.


Determining pH• The pH of a solution indicates its

concentration of hydronium ions (H3O+)

or the concentration of hydroxide ions (OH-).– The conc. of the two ions are related.

• If one increases, the other has decreased.

OH-H3O+

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More H30+ More OH-

Acids Bases

Acids are high in Hydrogen ion concentration

Bases are high in Hydroxide ion concentration

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Determining pH

Acid turns Blue Litmus Paper Red

Base turns Red Litmus Paper Blue

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Molarity

• (M) is the number of moles of substance per liter of solution.

The hydronium ion [H3O+]

concentration of apple juice is

0.001 mol/L or 1x10-3 M

pH of apple juice: ____, 3

The pH is the negative of the power of 10.

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Section 2:Reactions of Acids with Bases

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Neutralization

� Antacids relieve indigestion, usually caused by excess stomach acid.

� Antacid (a weak base) reacts with the strong acid in the stomach to produce a weaker acid, and thus the person will feel better.

AcidAcidAcidAcid----Base ReactionsBase ReactionsBase ReactionsBase Reactions

• A neutralization reaction is the reaction between an acid and a base.

A strong acid can neutralize a strong base.A weak acid can neutralize a weak base.

Acid + Base = Salt• Acid reacts with a base, hydronium ions

react with hydroxide ions to form water and a salt.

ACID + BASE �� SALT + WATER

Uses: cleaning, de-icing, ceramic glazes,

water softeners, fire extinguishers…

–HCl + NaOH = H2O + NaCl

• Made: by neutralization reactions

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Section 3: Acids, Bases, and Salts

in the Home

ACIDICStomach AcidLemon Juice

GrapesTomatoesBananas

Milk

BASICEggs

Baking SodaSoap

AmmoniaBleach

Oven Cleaner

NEUTRALPure Water

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• Concentrated sulphuric acid is extremely dangerous. It is found in car batteries.

Lemon juice contains citric acid and vinegar contains acetic acid.

Commercial descaling solutions contain strong and corrosive acids to remove

deposits of limescale.

Household AcidsHousehold AcidsHousehold AcidsHousehold Acids

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What Are Some Names of Acids?

� Acetic acid is found in vinegar

� Ascorbic acid is found in citrus fruits

� Hydrochloric acid is found in your stomach

� Phosphoric acid is found in fertilizers and the soft drinks you drink

� Nitric acid is used in some explosives like TNT

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Household BasesHousehold BasesHousehold BasesHousehold Bases

What Are Some Names of Bases?

• Ammonia (NH 3) is often found in cleaning products

• Potassium hydroxide (KOH) has many uses in industry, and can be a precursor to making soaps

• Sodium bicarbonate (NaHCO3) is found in baking soda

• Calcium carbonate (CaCO3) is found in antacids

• Sodium hydroxide (NaOH) is found in lye

KOH in pure form

Antacids neutralize stomach acids

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Acids Bases

Battery AcidStomach AcidLemon JuiceOrange Juice

Acid RainBlack Coffee

VinegarUrineSaliva

Sea WaterBaking SodaDrain CleanerOven Cleaner

AmmoniaSoap

Bleach

Hydrangeas are blue when grown in acidic soil and pink when grown in basic (alkaline soil)

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Which of these substances are acids?

Hydrochloric acid Vinegar

Lemon juice Bleach

Toothpaste Sulphuric acid

Bath salts Washing up liquid

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