What is Chemistry?Chemistry is… Defined as the science of materials and the changes that these materials undergo see examples on p. 7 of Ch. 1 A central science, meaning it is the basis of many other sciences/phenomena
The Study of ChemistryRequires patience and practice (!)Treat your performance in chemistry the way you do yourperformance in extracurricular activities from sports tomusic to video games; it is all about a little practice everyday. In general, intense cramming does not work well.Utilize your resources. Some suggestions: class Q & Atime, student study groups, peer tutoring, teachertutoring, online tutorials, additional chapter resourcesavailable on School Loop class siteThe light bulb moment will happen if you don’t give upwhen it first gets challenging Keep at it!
Introduction to Chemistry: Matter
What is Matter?All matter (what makes up the universe) consists of atomsAtoms are the basis of our study in chemistry. They consistof protons, neutrons, and electrons and are neutral (nooverall charge)Molecules are atoms bonded together that behave as oneunitElements consist of atoms of all the same type
Supplemental Vocabulary•Allotropes are elements with different configurations(arrangements) of atoms, leading to differing characteristics(example p. 28: Carbon—graphite vs. diamond)•Isotopes are atoms with differing numbers of neutrons intheir atoms (C-12 and C-14)•Ions are atoms with a charge due to a gain or loss ofelectrons
Phases (States) of MatterAll matter is found aseither a solid, liquid, orgas (also plasma, not inour realm of study)Phases of matter aredetermined by theamount space betweenthe particles of theobject.
Physical vs. Chemical Properties Physical Properties Chemical Properties Mass Reactivity Volume Enthalpy Density (M/V) Flammability Color Shape Boiling point And so many more!http://en.wikipedia.org/wiki/Physical_property
Physical vs. Chemical Changeshttp://meljo03.edu.glogster.com/physical-and-chemical-changes/ Physical Changes Chemical ChangesPhysical Changes are those Chemical Changes are thosethat impact only the that transform the substanceappearance of a substance but involveddo not affect the elements Example: burning paper (p. 32)involved or their arrangement Summary on p. 33or bondingExample: ripping paper
Evidence for a Chemical Change http://chemistry.about.com/od/demonstrationsexperiments/tp/myfavorites.htm1) Gas formation (bubble)2) Formation of a solid(precipitate, aka ppt)3) unexpected color change4) Light, heat, or sound emission5) Change in temperatureindicating a change in heat (endo-vs. exothermic rxns) NOTE: the only way to trulydetermine if a chemical reactionhas taken place is to analyze thechemical make up of the productsin relation to the reactants youstarted with
Elements, Compounds, & Mixtureshttp://www.sheffieldschools.org/Downloads/Atoms,%20elements,%20molecules,%20and%20compounds%20organizer.pdf Compounds consist of Mixtures differ from atoms of two or more compounds in that the different elements that differing are bonded together in a elements/compounds fixed ration (example: involved are not bonded H20 vs. H2O2) and can be separated (example: salt in water) (p. 36)
Elements, Compounds, & Mixtures
Types of MixturesHeterogeneous mixtures Homogeneous mixturesare ones in which the (solutions) are ones insolvent/solutes are easily which the substancedistinguishable looks uniform and the Include colloids and solvent/solutes are not suspensions, mixtures easily distinguishable that require microscopic inspection/time to view the separate parts of the mixture
Mixture VocabularyHeterogeneous Mixtures All mixtures consist ofinclude suspensions, solutes: what is beingcolloids dissolved and a solvent:Homogeneous mixtures are what the solute is beingtypically referred to as dissolved intosolutions Water is known as theAll mixtures can be universal solventseparated through Solutes can be solid, liquid,distillation and filtration or gas (example: soda hasmethods (p. 40) both syrup and carbon dioxide gas as solutes)
Ways to Separate a MixtureDecantingFiltrationEvaporationDistillationOther ways: use of magnets chromatography