MolecularSubstancesDissolve as Molecules

MolecularSubstancesAre composedOf non-metals

SolutionsDissolve asIndividual particles

Ionic substancesAre composed ofIonsOften a metal + non-metalOr poly atomic ion

NaCl Na2SO4

Dissolve as individual ions

Electrolytes

Recurrent theme!!!

All living things are heterogeneous

Review

Physical properties

Observed without converting to another substanceIntensive – characteristic of the substanceExtensive – depends on amount of substance present(mass and volume most important!)

Change of state – physical change – no change in Composition –

ice liquid water water vapor – still H2O

Other examples: hardness, mp bp, solubility, density, viscosity, color, taste, Smell (senses) –intensive

Chemical properties

• Relates to reactions of the substance– Rx change composition of substance

Chemical properties describe how it can change into other substances

• In a chemical change – atoms rearrange to form new substances with new chem/phy properties

• What does it react with– O2, acids, bases, oxidizers, reducers

• Does it rust, tarnish or combust?

Atoms rearranging

Physical vs Chemical Changes

SEPARATIONS

• Using differences in physical properties to separate pure substances in mixtures

• Bp, mp, solubility, magnetism• Pasteur – crystal separation

Difference in bp’s

Analogy ofRacing throughDowntownWith free beerstops

Paper chromatography

Aug ’07 news articleCat in nursing homeCurled up with dying Patients – How did it know?

Metabolites in breathMay be used to help Diagnose internal Infections/cancers!!

What common breath test is frequently used?

What condition can a nurse diagnose by smell of breath?

Coffee filter chromatogram --assignment

Temperature

• Temperature – degree of hotness or coldness! Intensity of energy

• Heat – energy – depends on– Temperature– Mass– Type of substance

• Equal masses of water and oil on similar burners, similar time – temp??

Temperature scales

• What scales are you familiar with

• How many degrees between fp and bp water in oF…. oC

• 2 patients are sick– A) 1o F fever– B) 1o C fever– Which is sicker???

Fever Why??Infection feversAre not likely to Cause “heat stroke

“Heat stroke”Overheating

Core body temps

Fevers: adults vsInfants…

practice

oC oF K

Boiling point N2 63

Cook pizza 425

Melting point ethanol -114

Freezing point Hg -37.89

Sig fig – ans should have same number of decimal places!!!