Course Hero Logo

topic_1_stoichiometric_relationships_1.1_to_1.3.pptx - IB...

Course Hero uses AI to attempt to automatically extract content from documents to surface to you and others so you can study better, e.g., in search results, to enrich docs, and more. This preview shows page 1 - 16 out of 104 pages.

Topic 1 Stoichiometric relationshipsIB CHEMISTRY
1.1 Introduction to the particulatenature of matter and chemical change• Atoms of different elements combine in fixed ratios to formcompounds, which have different properties from theircomponent elements.• Mixtures contain more than one element and/or compoundthat are not chemically bonded together and so retain theirindividual properties.• Mixtures are either homogeneous or heterogeneous.• Deduction of chemical equations when reactants and productsare specified.• Application of the state symbols (s), (l), (g) and (aq) inequations.• Explanation of observable changes in physical properties andtemperature during changes of state.OBJECTIVES
Law vs theoryBoth are developed from experiments. Both haveexceptions. Both can be modified or rejected.Theory:An explanationthat provides anunderstanding across a range of phenomena anddisciplines.Law:A descriptionof regular patterns of behavior.
Law of definite proportions‘A compound always contains thesame proportion of elements bymass’Joseph Louis Proust, Frenchchemist1794 showed experimentally thatartificial and natural coppercarbonate had the sameproportion of weights between Cu,C, and O.
But... what about thiscompound?Berzelius a Swedishchemist disagreed withProust.Non-stoichiometriccompounds (mainlyinorganic solids andpolymers) as well asisotopes form exceptionsto the ruleEg. FeO is usually Fe0.84Odue to Fe in differentstates (Fe2+and Fe3+)
Principle of Occam’s razorWilliam of Ockham was and Englishmonk (1287-1347 CE).‘A theory should be as simple aspossible while maximizingexplanatory power.’(Shaving away the unnecessary)Why did Proust win out overBerzelius?
Element:A substance composed of atoms having anidentical number of protons in each nucleus.Atom:Smallest part of an elementCompound:2 or more elements chemically bondedtogetherMixtures:Contain more than one element an/orcompound that are not chemically bonded togetherand so retain their individual properties. Two types:Homogenous– have uniform propertiesHeterogenous– have non-uniform propertiesTerminology
Background image
TerminologySolid (s), Liquid (l), Gas (g), Aqueous (aq) –dissolved in water
States of matter
Changes of statemeltingfreezingVaporization(boiling vsevaporation)condensationsublimationdeposition
Heating curvesSI unit for temperature is thekelvin (K)which is°C + 273.150100500-50Time/sThis flat line demonstrates thesubstance is pureEnergy added at phase changegoes into breaking interparticleforces NOT raising temperature
Background image
Law of multiple proportions‘If two elements form more than onecompound between them, then theratios of the masses of the secondelement which combine with a fixedmass of the first element will be ratios ofsmall whole numbers’eg. CO and CO2John Dalton, English chemistAn improvement built upon Proust’s lawof definite proportions and Lavoisier’s lawof conservation of mass. These three lawsthen then form the basis for chemicalformulae, names, and stoichiometry!
Experimental evidence for stoichiometry:

Upload your study docs or become a

Course Hero member to access this document

Upload your study docs or become a

Course Hero member to access this document

End of preview. Want to read all 104 pages?

Upload your study docs or become a

Course Hero member to access this document

Term
Spring
Professor
carlson
Tags
Chemistry, Atom, Mole, Stoichiometry, Amount of substance

Newly uploaded documents

Show More

Newly uploaded documents

Show More

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture