Introduction
Chemistry |
study of matter, its properties, changes it undergoes, and energy associated with its changes |
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central science. everything is composed of matter |
Matter |
takes up space and has mass |
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anything composed of atoms and molecules |
Atom |
building block of matter |
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always in constant motion |
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has endless combinations |
States of Matter
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Def Vol |
Def Shape |
Inc Temp Result |
Compressibility |
Solid |
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small |
x |
Liquid |
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x |
small |
x |
Gas |
x |
x |
large |
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Chemical Properties of Matter
observed when chemical makeup is altered |
Ability to Burn |
Ability to Decompose |
Ferment |
Reacts With |
Physical Properties of Matter
can be measured without changing the substance or chemical composition |
Color |
Odor |
smell |
Luster |
how shiny |
Malleability |
to be beaten into thin sheets |
Ductility |
to be made into thin wires |
Physical |
use of senses |
2 Properties Under Physical Property
Extensive |
amount of matter in the sample |
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mass, volume, no. of cal present |
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identifiers of unknown matter |
Intensive |
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depends on state of matter |
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density, hardness, melting point, boiling point |
Evidence of Chemical Change
Absorption/Release of Energy |
Color Change |
Light Evolution |
Production/Liberation of Gas |
Formation of Precipitate |
Law of Conservation of Mass
-mass of products = mass of reactants. Always |
-no change in quantity despite chemical/physical change |
-not created nor destroyed. converted from one substance to another |
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Classification of Matter
Classification of Matter
Pure Substance |
cannot be physically separated |
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elements and compounds |
Mixture |
2+ substances physically combined |
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constant BP and MP nonexistent |
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retains characteristic properties of components |
Heterogenous Mixture |
can be physically separated |
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components are distinguishable |
Homogenous Mixture |
particles distributed evenly throughout |
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components not distinguishable |
Separating Techniques/Methods
-to remove unwanted particles |
-to obtain important substance |
-to obtain pure substances |
Mechanical Separation |
manual separation based on physical properties |
Magnetic Separation |
when component has magnetic property |
Filtration |
diff of solid particle size |
Decantation |
diff densities, pour out liquid, leave solid |
Distillation |
2 substances have diff BP |
Evaporation |
vaporize liquid, leave reside behind |
Density Separation |
less dense floats, more dense sinks |
Centrifuge |
circular motion to sink denser components |
Paper Chromatography |
diff in solubility |
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faster flow through solid = lower solubility |
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Parts of Lab Report
Theoretical Framework |
main idea (statement of problem) |
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introduce experiment, discuss theory, law, or concept behind what's investigated |
Materials & Procedure |
list of all items used |
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paragraph or narrative explaining details |
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procedure |
Data & Results |
data tables, figures with titles, short descriptions |
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label all tables, graphs, charts |
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attach separate sheet if necessary |
Analysis & Discussion |
discuss what results mean |
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answer to all guide questions (par form) |
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follow format in objective type items |
Conclusion |
answer statement of the problem |
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summary of the data |
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discuss insights, application to real-life situations |
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possible errors (experimental errors, scope & limitations, ) & recommendations |
References |
CSE citation style |
Reflection |
each member needs own reflection |
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go beyond reflection questions given |
Contribution |
tabulate contributions of each member |
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which part conducted |
Atomic History & Subatomic Particles
Ancient Greek Philosophers |
Atomists |
- everything is made of tiny indivisible particles |
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Leucippus |
- matter is composed of 2 indivisible things, atoms, and void |
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Democritus |
- atoms from one object are different from another object |
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-Democritus' Building Blocks (first figure for atoms) |
Natural Elementalists |
- everything is made of natural elements |
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Empedocles |
- everything is made of water, earth, fire, & air |
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Aristotle |
- everything is infinitely divisible, and made of water, earth, fire, air, and aether |
John Dalton's Postulates
Indivisible Atoms |
elements are made of small indivisible particles called atoms |
Mass & Properties |
mass & properties of all its other atoms are same, for all elements |
Atomic Ratios |
atoms in given compound are present in a constant whole-number ratio |
Reactions |
atoms are not created nor destroyed; they combine, separate, or rearrange |
History of Atomic Models
Dalton's Atom |
a singular circle |
Thomson's Plum Pudding Atom |
electrons needed a positive "something" to counter the charge |
Rutherford's Nucleus Atom |
discovered the nucleus, something that deflected the particles |
Bhor's Planetary Model |
discovered shells and energy levels |
Bhor's Planetary Model v2.0 |
discovered neutrons |
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light elements bombarded with alpha particles will produce lots of ionizing radiation |
Atom Structure
Atom |
electrically neutral |
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spherical |
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contains, protons, neutrons, (+) charged nucleus surrounded by (-) electrons |
Electrons (e- or beta) |
move rapidly around nucleus (probability cloud) |
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Charge: -1.602x10-19C |
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Mass: 9.109x10-31 kg |
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Diameter: ~10-18m |
Protons (p+ or H+) |
all (+) charge of nucleus results from protons |
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Charge: +1.602x10-19 C |
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Mass: 1.672x10-27kg |
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Diameter: ~10-15m |
Neutrons (n0) |
no charge |
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Mass:1.674x10-27kg |
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Diameter: ~10-15m |
Atomic Number (Z) |
=no. of p+ in nucleus = no. of e- in atom |
Mass Number (A) |
=p+ + n0 in nucleus (there are no electrons in the nucleus because nucleus us + charged) |
Isotope |
isos = same, topos = place |
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different no. of n0, but same no. of p+ |
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