Physical Property Describes form or behavior of matter

Independent of sample size (density, melting point, boiling point, etc.) Intensive Properties

Depend on how much stuff! (Mass & Volume) Extensive Properties

Chemical Property Describes how matter interacts with other matter

Chemical Change Identity Change A new substance is formed.

Chemical Change Identities change! Note: particle diagram shows conservation of mass: same # of each type of atom on reactant and product sides.

Monatomic One-atom Molecule

2 or more uppercase letters in formula Compound

Physical Change Identity stays the same

H 2 O(l)  H 2 O(g) Phase changes are physical changes. Identity stays the same.

2H 2 O(l)  2H 2 + O 2 (g) Identity changes. Chemical change.

Diatomic 2-Atom Molecule

Smallest particle of an element that retains the properties of the element and that can participate in a chemical reaction. Atom

Gases Take the shape & volume of their container

Physical Constant Physical property expressed with a # & unit. Independent of sample size.

Liquids Definite volume but no definite shape

Solids Definite volume & definite shape

Compound 2 or more elements chemically combined

Element Cannot be broken down into anything simpler by ordinary chemical or physical methods

Mixture Physical combination of 2 or more pure substances.

Pure Substances Elements & Compounds

Pure Substances Type of Matter? The particles in each case are identical to each other.

Mixtures Heterogeneous or Homogeneous

Heterogeneous Mixtures Type of Mixtures?

Homogeneous Mixtures! Type of Mixtures?

Pure Substance! Mixture or Pure Substance?

Distillation Physical method of separating mixture of 2 or more liquids based on differences in boiling points.

Solution Homogeneous Mixture. Liquid & gas phase solutions transmit light. Look translucent. Do not separate on standing.

Suspension Heterogeneous Mixture. Scatter light. Look cloudy. Need to be shaken or stirred. Separate on standing.

NaCl(aq) Homogeneous Mixture. NaCl dissolved in water.

NaCl(s) Pure substance. NaCl in the solid phase.

Variable Composition Mixture

NaCl(l) Pure substance. NaCl in the liquid phase.

NaCl(g) Pure substance. NaCl in the gas phase.

Homogeneous Uniform, constant, the same throughout.

Always Homogeneous Pure substance: Element or Compound

Filtration Physical separation technique used to separate heterogeneous mixtures. Based on differences in particle size.

Sorting Physical separation technique used to separate heterogeneous mixtures. Based on differences in appearance.

Definite & Unique Properties Pure substance. Element or Compound.

Broken into components by chemical decomposition reaction Compound

Definite Composition Pure substance. Element or Compound.

Separated by physical technique Mixture

Triatomic 3-atom Molecule

May be homogeneous or heterogeneous Mixture

Compare pure substances & mixtures Pure SubstancesMixtures Unique PropertiesNo unique properties Definite CompositionVariable Composition Always Homogeneous in a single phase May be homogeneous or heterogeneous Elements cannot be broken down. Compounds can be separated into elements using chemical separation techniques. Can be separated into component substances using physical methods.

Density, melting point, boiling point Examples of physical constants

Law of conservation of mass (lab scale) Total Mass of Reactants = Total Mass of Products

Law of conservation of mass (microscale) Total # of atoms of each type on reactant side =Total # of atoms of each type on reactant side = Total # of atoms of each type on product sideTotal # of atoms of each type on product side

No new properties. Properties are a mix of properties of components. Mixture

C 6 H 12 O 6 (s)  C 6 H 12 O 6 (aq) Equation represents dissolving. Dissolving is a physical change.

Physical Properties Used to identify substances.

Atoms can vibrate back & forth about a fixed position. Solid state

Ways to separate heterogeneous mixtures Sorting Filtration Crystallization Evaporation Distillation Chromatography Differences in density Differences in magnetic properties Differences in solubility

Change of phase terms Evaporation = l to g Freezing = l to s Melting = s to l Condensation = g to l Boiling = l to g Deposition = g to s Fusion = s to l Sublimation = s to g

Names of Phase Changes Melting or Fusion Evaporation, Boiling, or Vaporization

Molecules are relatively far apart from each other & can move from place to place. Gas Phase

Molecules are pretty close, but have enough room to slide past each other. Liquid Phase

One substance dissolved in another substance Solution

Homogeneous mixture in a single phase Solution

CANNOT be separated by filtration. Liquid phase MUST be evaporated. Solution

(aq) means dissolved in water It’s a solution! NaCl(aq)

Heterogeneous mixture of a solid in a liquid Must be shaken or stirred constantly Looks murky or opaque Suspension

Solid phase can be separated by filtration Suspension

Heterogeneous Mixture SiO 2 (s) + NaCl(aq) Separate the sand by filtration. Evaporate the water to retrieve the salt.

Phase at room temperatrue Physical property

Chromatography Physical separation technique based on differences in intermolecular forces.

Vapor Gas phase of a substance that is usually a liquid at room temperature.

Names for some chemical changes Corrosion, Decomposition, Neutralization, Burning, Fermentation, Rotting

# of atoms of each element before = # of atoms of each element after Law of Conservation of Mass

Percent Part X 100% Whole

1 upper case letter in formula Element

Cutting, Crumpling, Tearing, Pulling into wire, Hammering into sheet Examples of physical changes

Phase Changes Examples of physical changes

Evidence of Chemical Change Production of heat & lightProduction of heat & light Formation of a gas (bubbles)Formation of a gas (bubbles) Formation of a precipitateFormation of a precipitate Change in identifying propertiesChange in identifying properties

Opposite of dissolving. Solid comes out of solution. Precipitation

Particles arranged in a regular geometric pattern. Solid

Potential Energy S L G Endothermic Exothermic

The solid phase: the particles are closest together! (Molecules are always attracted to one another.) For a given substance, which phase has the lowest potential energy?

They are the same size! How do the centigrade degree and the Kelvin compare?

Phase change: sublimation Endothermic H 2 O(s)  H 2 O(g)

Phase Change: condensation Exothermic H 2 O(g)  H 2 O(l)

Phase change: melting endothermic H 2 O(s)  H 2 O(l)

CO 2 (s) or dry ice and I 2 (s) Two common substances that sublimate?

Mixture Pure Substance

Molecules have potential energy as a result of their structure and composition. Chemical Potential Energy