Properties of MatterChapter 2 & 8

“Properties of Matter” • Matter is

anything that has mass and occupies space.

– Matter is made of atoms which are the smallest particles that have the properties of an element.

“Solutions and Other Mixtures”

• Pure substances are any matter that has a fixed composition and definite properties.

– Cannot be broken down by physical changes.

– Made of:• Elements are substances that

cannot be broken down into simpler substances.

• Compounds are substances made of atoms of more than one element bound together.

• Molecules are the smallest unit of a substance that exhibits all of the characteristics of that substance.

“Solutions and Other Mixtures”

• A mixture is a combination of one or more pure substances.

– Can be broken down by physical changes.– While compounds are different from the elements

that make it, mixtures may have some physical and chemical properties similar to the pure substances.

+ + =sour sweet wet sour, sweet & wet

Heterogeneous Mixture• Heterogeneous

mixtures are mixtures that are not uniformly mixed.

Heterogeneous Mixture• Suspensions are

heterogeneous mixtures that look uniform when you shake them, but will separate out if you let them set.

Heterogeneous Mixture• Liquid mixtures

that are heterogeneous are called immiscible. This means that the two or more liquids in the mixture do not mix into each other.

• Colloids are heterogeneous mixtures of very tiny particles of pure substances that are dispersed in another substance but do not settle out.

Heterogeneous Mixture

Heterogeneous Mixture• Emulsions are

any mixture of immiscible liquids in which the liquids are spread throughout one another.

• The immiscible liquids stay mixed because of an emulsifier.

Homogeneous Mixture• Homogeneous mixtures are

uniformly mixed.

Homogeneous Mixture• Liquid mixtures that

are homogeneous are called miscible. This means that the two or more liquids in the mixture are able to dissolve into each other in various proportions.

Homogeneous Mixture Miscible solutions can be

separated using distillation.

Distillation takes advantage of different boiling points.

Distillation works by boiling off and condensing the substance with the lowest boiling point.

Homogeneous Mixture• Solutions are

homogeneous mixtures of two or more substances uniformly spread throughout a single phase.

– A solution has 2 parts:• Solvent: dissolves a

substance.• Solute: is dissolved.

solvent

solute

Homogeneous Mixture• An alloy is a solid or liquid mixture

of two or more metals.

Brass Bronze

“Dissolving and Solubility” • Solubility is

the ability of one substance to dissolve in another at a given temperature and pressure.

“Dissolving and Solubility” • Concentration is the amount of a particular substance in a given

quantity of a mixture, solution, or ore.– A concentrated solution will have a large quantity of dissolved solute.– A dilute solution will have a small quantity of solute dissolved in a large

volume of solvent.– Saturated solutions are solutions that cannot dissolve any more solute at the

given conditions.– Before this solutions are considered unsaturated.– Super saturated solutions occur when you heat a solvent up at a very high

temperature and dissolve solute to saturation. When it cools it holds more solute than normally possible.

“Dissolving and Solubility” • “Like only dissolves

like.”• Polar substances are

only soluble in polar substances.

• Nonpolar substances are only soluble in nonpolar substances.

• Polar substances like water will not mix with neutral things like oil. Oil is considered nonpolar.

“Dissolving and Solubility” • Factors that can increase the

rate of solubility:– Substances with a larger surface

area dissolve faster.• Example: sugar granules dissolve

faster than sugar cubes.

– Stirring a solution will also make it dissolve faster.

– Heating a substance adds more energy to its molecules making them move faster in liquid. This causes a more rapid transfer of energy from a solvent to a solute.

• Example: dissolving sugar into tea.

“Dissolving and Solubility” • We can visually interpret different

concentrations of soluble substances using what is called a solubility curve.

– These curves show how the amount of dissolved solute changes with temperature.

Acids, Bases, and SaltsChapter 9

Acids, Bases and PH• Acids are a substance that

donates hydrogen ions, H+, to form hydronium ions, H3O+, when dissolved in water.

– Examples: sulfuric acid, hydrochloric acid, acetic acid

Acids, Bases and PH• Properties of an acids:

• Taste sour.• Turn blue litmus

paper red.• Destroy the chemical

properties of bases (neutralization).

• Conduct an electric current.

• Produce hydrogen gas when they come in contact with an active metal.

Acids, Bases and PH• Bases are substances that either

contains hydroxide ions, OH-, or reacts with water to form hydroxide ions.

– Examples: Sodium hydroxide, potassium hydroxide, and ammonia

Acids, Bases and PH• Properties of a

base:– Taste bitter.– Turn red litmus

paper blue.– Destroy the

chemical properties of acids (neutralization).

– Conduct electric current.

– Feel slippery.

Acids, Bases and PH• Strong acids and

bases fully ionize in water, meaning they form as many hydronium or hydroxide ions as they possibly can.

• Weak acids and bases do not fully ionize. This means there are less ions created in the water.

Acids, Bases and PH• Strong acids and

bases have more dissolved charged ions in a solution and therefore have a higher conductivity.

– Conductivity is the ability to conduct electricity.

Acids, Bases and PH

• pH is a measure of the hydronium ion concentration in a solution.

– The pH scale typically ranges from 0-14.• Neutral solutions have

a pH of 7.• Below 7 is acidic.• Above 7 is basic (also

called alkaline).

Litmus PaperBlue and Red Litmus Paper

Natural (Cabbage Juice)

Acids, Bases and PH• Indicators are

compounds that can reversibly change color in a solution depending on the concentration of H3O+ ions.

Reactions of Acids and Bases

• A neutralization reaction is a reaction in which hydronium ions from an acid and hydroxide ions from a base react to produce a solution that is more neutral than either of the reactants.

– Products: water and a salt

Reactions of Acids and Bases

• A salt is an ionic compound of cations bonded to anions, other than oxide or hydroxide anions.

Acids and Bases in the Home

• Acids and bases for cleaning.

– Soap is a base that allows us to wash off oil with water.

• A droplet of oil can stay suspended in water because the polar ends of the soap dissolve in water and the nonpolar ends dissolve in oil.

Acids and Bases in the Home

– Detergents are bases that are used instead of soaps for clothing and dishes because when used with “hard” water (water containing dissolved salts) detergents do not create an insoluble soap scum.

Acids and Bases in the Home

– Ammonia solutions are bases made by dissolving ammonia gas through water. The hydroxide ions in this solution interact with greasy dirt to form an emulsion of with water.

Acids and Bases in the Home

– A disinfectant is a substance that kills harmful bacteria and viruses.

• Bleach is base that is a disinfectant.

Acids and Bases in the Home• Acids and bases

are used in healthcare.

– Acids: ascorbic acid (vitamin C), acetylsalicylic acid (aspirin)

– Bases: sodium hydrogen carbonate and magnesium hydroxide (milk of magnesia) are both antacids.

Acids and Bases in the Home• Acids and bases are

used in the kitchen.– Acids: citric acid

(prevents browning in apples), marinades (vinegar and wine tenderize meat), lactic acid (changes milk to yogurt).

– Bases: sodium hydrogen carbonate (baking soda), baking powder, potassium hydroxide (lye, used as a drain cleaner).