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classification of matter and temperature
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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!!!