Compounds Student Learning Objectives: define what a compound is define what a compound is compare elements and compounds compare elements and compounds.

CompoundsCompoundsStudent Learning Objectives: Student Learning Objectives: •define what a compound isdefine what a compound is•compare elements and compoundscompare elements and compounds•describe how compounds differ from the describe how compounds differ from the elements they are made fromelements they are made from

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Matter Concept Map

MATTER

Can it be physically separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture Compound Element

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition uniform?

noyes

Colloids Suspensions 22

What do these have in What do these have in common?common?

ElementElement CompoundCompound

What is different about them?What is different about them?Discuss with your partner.Discuss with your partner.

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Pure SubstancePure Substance

Substance in which there is only Substance in which there is only oneone type of particle type of particle

Particles are the same as other Particles are the same as other particles in that substance. particles in that substance.

Element particle Element particle atom atom Compound particle Compound particle molecules molecules Water is a compound because it is Water is a compound because it is

made of molecules that are all the made of molecules that are all the same.same.

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ElementsElements Pure substance that Pure substance that cannotcannot be broken down into be broken down into

simpler substances by chemical or physical simpler substances by chemical or physical means.means.

Composed of the same atoms.Composed of the same atoms. Represented by a chemical symbolRepresented by a chemical symbol

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CompoundsCompounds

Two or more elements that are chemically Two or more elements that are chemically combined and combined and cancan be broken down be broken down

Pure substances, made of Pure substances, made of moleculesmolecules Represented by a Represented by a chemical formulachemical formula: :

water = Hwater = H22OO

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Compounds have a Compounds have a Specific Ratio of ElementsSpecific Ratio of Elements

The molecules have same number of atoms of The molecules have same number of atoms of each element that makes up the formula. each element that makes up the formula.

The subscript tells the number of atoms of each The subscript tells the number of atoms of each element in the molecule element in the molecule

Examples:Examples: Water: HWater: H22O = 2 H atoms and 1 O atom O = 2 H atoms and 1 O atom Peroxide: HPeroxide: H22OO22 = 2 H atoms and 2 O atoms = 2 H atoms and 2 O atoms Carbon dioxide: COCarbon dioxide: CO22 = 1 C atoms and 2 O atoms = 1 C atoms and 2 O atoms Carbon monoxide: CO = 1 C atom and 1 O atomCarbon monoxide: CO = 1 C atom and 1 O atom

Different ratio of the same elements makes a Different ratio of the same elements makes a different compounddifferent compound 77

Compounds have Compounds have Unique PropertiesUnique Properties

Compounds and their elements have Compounds and their elements have different propertiesdifferent properties

Na + Cl = NaClNa + Cl = NaCl (salt) (salt)(soft, silvery, reactive metal) + (green poisonous gas) = (white, crystalline, edible solid)(soft, silvery, reactive metal) + (green poisonous gas) = (white, crystalline, edible solid)

Compounds can be identified by their propertiesCompounds can be identified by their properties Salt is a white crystalline solid with a high mpSalt is a white crystalline solid with a high mp

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DiscussDiscuss

2H2H22 + 0 + 022 2H 2H22OO

Discuss with your partner the properties of hydrogen Discuss with your partner the properties of hydrogen and oxygen and how they compare to the properties of and oxygen and how they compare to the properties of waterwater

Hydrogen: clear, colorless, odorless, explosive gasHydrogen: clear, colorless, odorless, explosive gas Oxygen: clear, colorless, odorless gas that Oxygen: clear, colorless, odorless gas that

supports burningsupports burning Water: clear, colorless, odorless liquid that is used Water: clear, colorless, odorless liquid that is used

to put out fires.to put out fires.

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Compounds Compounds CAN CAN Be Broken DownBe Broken Down

Compounds Compounds cancan be broken down by be broken down by chemical changechemical change such as such as

• Chemical reactionChemical reaction• HeatingHeating• ElectrolysisElectrolysis

Compounds Compounds cannotcannot be broken down by be broken down by physical changephysical change such as such as

• crushing or boiling. crushing or boiling.

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DiscussDiscuss

Discuss with your partner what happens Discuss with your partner what happens when you boil water? Is boiling a physical when you boil water? Is boiling a physical or chemical change?or chemical change?

When water is boiled, it changes to water When water is boiled, it changes to water vapor (same substance, Hvapor (same substance, H22O) so boiling is O) so boiling is

a physical change.a physical change.

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Ionic CompoundsIonic Compounds Metal + nonmetalMetal + nonmetal Electrons are transferred from metal to Electrons are transferred from metal to

nonmetal forming + and - ionsnonmetal forming + and - ions Opposite charges attractOpposite charges attract Formula: + ion comes firstFormula: + ion comes first Properties of ionic compounds: Hard, Properties of ionic compounds: Hard,

brittle, high MP & BPbrittle, high MP & BP

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DiscussDiscuss

Discuss examples of ionic compounds Discuss examples of ionic compounds with your partner.with your partner.

Examples: Examples: NaNa++ClCl- - or NaCl Sodium Chloride or NaCl Sodium Chloride MgMg+2+2OO-2 -2 or MgO Magnesium Oxideor MgO Magnesium Oxide LiLi22+1+1SS-2 -2 or Lior Li22S Lithium SulfideS Lithium Sulfide

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Covalent CompoundsCovalent Compounds

Nonmetal + nonmetalNonmetal + nonmetal NO ions formed NO ions formed Electrons are Electrons are sharedshared Soft, Low MP and BPSoft, Low MP and BP Discuss examples with your partnerDiscuss examples with your partner

COCO22 Carbon dioxide Carbon dioxide

HH22O Water (Dihydrogen monoxide)O Water (Dihydrogen monoxide)

NHNH3 3 Ammonia (Nitrogen trihydride)Ammonia (Nitrogen trihydride)

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321 Review321 Review

Complete the Complete the 321 Review321 Review

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