Midterm – Chemistry – Flashcards

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% Compostition
answer

  • percent per mass of each material found in an item
  • used in mining to determine if a ore is profitable to mine and to find how much of an element is in the ground

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% concentration by mass
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  • mass of solute/total mass x 100
  • also called pph (parts per hundred) 

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Accuracy
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the average of data
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Acids
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  • H as cation
  • sour 
  • react with metals

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Activity Series
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  • elements ranked in order of relative reactivity
  • the more reactive and element, the harder it is to find it in a pure state

 

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Allotropes
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  • 2 or more forms of an element that have difference physical or chemical properties
  • two forms must be in same state of matter
  • diff. properties caused by dif arrangements of atoms 

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Alloy
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  • Solid combo of 2 or more metal elements
  • considered a solid solution
  • one way of modifying properties of an element
  • brass: copper and zinc
  • bronze: copper, tin, and zinc
  • steel: iron and carbon
  • 14 carrot gold: gold, copper, and silver
  • white gold: gold and palladium 

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Anode
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  • The location at which oxidation is occurring
  • known as positive electrode

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Atom Interaction
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  • atoms have some attractions between other atoms
  • attractions are not chemical bonds
  • the stronger the attraction, the harder it is to separate
  • explains differences in boiling and melting points

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Bases
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  • have OH- as anion, or they produce OH- when dissolved in H20
  • bitter
  • feels slippery

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Boiling Point
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  • metals: as you go down a fam, boiling point goes down 
  • nonmetals: as you go down a fam, boiling point does up
  • carbon family has highest boiling point

 

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Cathode
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  • location at which reduction is occurring
  • known as negative electrode

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Chemical Change
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  • any change or property that changes the chemical makeup of the matter
  • signs of chem change: color change, precipitate, fizzing/bubbling, temp change

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Coatings
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  • paints, varnishes, and shellacs
  • applied late in manufacturing process
  • 3 components: pigment, solvent, and resin
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    Colloids
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    • heterogenous
    • suspended material

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    Covalent Bonds
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    • bonds share electrons
    • substances held together by covalent bonds
    • molecular substances do not dissolve in H20

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    Demetri Mendeleev
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    father of the periodic table
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    Doping
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    adding impurities to pure forms of semiconductors in order to increase their conductive properties
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    Earth's Compostition
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    • atmosphere- air
    • hydrosphere- water
    • lithosphere- earth
    • crust- top layer of earth, solid
    • mantel- (Mg and Fe), fluid like
    • Core- (Fe and Ni), solid

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    Electrode
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    a conductor through which electricity enters/leaves and object, substance, or region

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    Groups/Families
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    • vertical columns on periodic table
    • group 1: alkali metals (+1 charge)
    • group 2: alkaline metals (+2 charge)
    • group 17: Halogens (-1 charge)
    • Group 18: Noble Gasses (no charge)
    • Group 3-12: Transition Metals

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    How do we know if it is profitable to mine a given site?
    answer

    1. amount of useful ore at site
    2. percent of metal in an ore
    3. type of mining process needed
    4. distance from mine to refining facility and markets
    5. metals supply vs. deman

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    Kelvin
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    degrees;celsius;+ 273.15
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    Life Cycle of a Material
    answer

    1. raw material obtained
    2. raw material refined
    3. synthesized into desired material
    4. made into products
    5. reused, recycled, or discarded

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    Matter
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    anything that has volume and mass
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    Mineral
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    • solid compounds containing the element or group of elements of interest
    • found in ore

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    Mixtures
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    • homogenous- like, same make-up, look like on things
    • heterogenous- diff, diff make-up, look like multiple things

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    Modifying Properties
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    Can be modified by synthesizing material with other elements or compounds at molecular level
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    Molar Mass
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    • g/mol
    • the mass of one mol of a compound in grams per mole
    • 1 molecule contains 2 atoms of H and 1 atoms of 0
    • 1 mole of water contains 2 moles of H and 1 mole of 0
    • equal to atomic mass with units of grams

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    Mole
    answer

    • counting unit
    • represents a number of atoms, molecules, or formula units large enough to be conveniently weighed or measured in the lab

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    New Periodic Table
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    • based on atomic number
    • atomic number=number of protons
    • distinguishes atoms of different elements
    • distinguishes atoms of different atoms

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    Nitrogen;Family
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    bonds with other elements the most
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    O in Oxide
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    • same amounts in elements of the same family

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    Ore
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    naturally;occurring;rock or mineral that can be mined and from which it is profitable to extract metal or other material
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    Original Periodic Table
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    • based on atomic mass
    • worked well for light elements but isotopes caused problems

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    Oxidation Reduction Reactions (Redox Rxns)
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    • reactions that involve the transfer of electrons among reactants
    • reductions: chem change in which species gains one or more electrons, aka oxidizing agent
    • oxidation: chem change in which species looses one or more electrons, aka reducing agent
    • *oxidation ; reduction must occur together

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    Physical Changes
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    any property or change that does not change the chemical makeup of the matter
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    Pigments
    answer

    • used in coatings
    • provides color

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    Plating
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    • uses direct current electricity to cause REDOX reaction
    • used to coat surface of material using chem bonds
    • generally known as electroplating
    • ex: steal chrome on cars

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    Powder Coating
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    • newest form of coating technology
    • solvent removed and pigment and resin are applied in powder form using spray guns and electricity

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    Precision;
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    reproducible;results
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    Properties of Metalloids
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    mix between properties of metals and nonmetals
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    Properties of Metals
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    • malleable
    • shiny/metallic luster
    • conduct
    • very reactive w/ acids
    • reacts w. CuCl2

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    Properties of nonmetals
    answer

    • brittle
    • dull;
    • non conductive
    • does not react w/ acids
    • does not react w/ CuCl2

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    Pure Substances
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    ;

  • compounds- 2+ elements
  • elements- simplest form of matter
    • ;

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      Reactivity trend on the Periodic Table
      answer

      • francium(Fr)= most reactive element on p.table
      • flourine(Fl)=most reactive nonmetal on p.table

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      Reading a Scale
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      remember, if;meniscus;is on a line, put a 0 at the end;
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      Refine
      answer

      • the process of converting a combined metal in a mineral or ore to a free state
      • pyrometallurgy: first method used, uses fire
      • hydrometallurgy: uses water
      • electrometallurgy: uses electricity;

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      Renewable Resources
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      can eventually be replenished through natural or artificial process, ex: food or lumber
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      Rows/Periods
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      horizontal rows on the periodic table
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      Rules of Balancing Equations
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      • start w/ most complicated compound
      • keep polyatomic ions together if possible
      • leave elements by the themselves to the very end
      • if it is not working go back ; increase coefficient in front of most complicated compound and start over
      • *H20 can be written as HOH

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      Semiconductors
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      • elements that are less conductive than metals but still have some conductive properties
      • silicon, geranium, tine, gallium arsenide, cadmium sulfide
      • silicon=most common semiconductor, found in most electronics

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      Significant Digits
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      • any non-zero number is significant
      • ex: 202= 3 sig digs, zeros sandwiched by sig digs are significant
      • zeros to the left are never significant
      • ex: 426.30=5 sig digs, zeros to the right are sig if they are after the decimal
      • x ; / =# in operation w/ smallest # of sigdigs limits the answer
      • + ; - = # w/ smallest # of decimals limits the answer

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      Solvent
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      • does the dissolving (ex: water)
      • charges dissolve other things w/ charges
      • no charge (non polar) dissolve polar things
      • gasses dissolve in water

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      Solvent
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      • used in coating
      • allows application in liquid form

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      Supply and Demand
      answer

      • need water to grow crops and boil eggs
      • need water to make metal
      • amount of rain or snow does not always correspond w/ high water use

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      Suspension
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      • heterogenous
      • material settles out

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      Thin Films
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      • distinguished by very small thickness on a surface
      • may only be 1 0r 2 atoms/molecules thick
      • used in optic and electronic applications
      • ex: UV protective film

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      Tyndall Effect
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      lights scattered by solids, shows colloids

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      Waste Management
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      • recycle: convert waste into reusable material
      • reuse: reuse material for its initial material before it becomes waste

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      Ways to separate mixtures
      answer

      ;

      1. filtration: use porous membrane
      2. density separation: use when mixture of layers, decanting=to pour one layer off, helpful w/ oil and water
      3. Charcoal;Absorption: when dissolved ; suspended particles are attracted to the surface of charcoal, removes smells, color, ; taste
      4. Magnetism: put magnet in water, can be used to separate iron ; water
      5. Distillation

      ;

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      Where is the Earth's Water?
      answer

      • 97%= ocean
      • 2nd largest= ice caps
      • water can be found in gaseous, liquid, or solid state
      • water from river or lake= surface water
      • well= ground water

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      Why were gold, silver, and copper the first metals to be discovered?
      answer
      they are chemically inert, and found in their free state in nature
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      charge
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      protons - electrons
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      chemical symbols
      answer
      represent identity of an atom
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      covalent compounds
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      • dissolve down to molecules
      • can have partial charges= polar covalent
      • ionic substance do not dissolve in non-polar covalent

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      density
      answer

      • mass/volume
      • on a graph density=slop

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      dimensional analysis
      answer

      • factor label method
      • start w/ # given in problem
      • multiply by factor (ratio of 2#'s that = each other)

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      electrons
      answer

      ;

      • negatively charged
      • usually equal to number of protons
      • # of electrons and arrangement determines chem and physical props, elements in the same family have similar props
      • metals tend to lose electrons from ions
      • nonmetals share or gain electrons
      • found in electron cloud
      • no mass

      ;

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      equations
      answer
      show chem.;interactions;of matter
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      formulas
      answer
      identify the type ; # of atoms found in molecule
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      half reactions
      answer

      • reactions that include the movement of electrons
      • ex: Cu+2 + 2e- ---> Cu0 

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      heavy metal ions
      answer

       

      • metals on p.table w/ high atomic mass
      • pb=lead, Hg= mercury, both are neurotoxins

       

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      ion
      answer

       

      • when protons do not equal electrons
      • cation= positive charge
      • anion= negative charge
      • 2 positive/ 2 negatives repel
      • ions can be made of 2 or more atoms
      • ions w/ 2 or more atoms= polyatomic atoms
      • ionic bonding=transfer electrons which cause chem attractions due to charges formed
      • ionic compounds=formula units (not molecules)
      • *cations are always written 1st

       

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      ionic compound
      answer

       

      • metal& nonmetal
      • when ionic substances dissolve, they dissociate

       

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      isotope
      answer
      2 atoms with same # of protons but different # of neutrons
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      law
      answer
      states summary of observed behavior, can't be broken
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      law of conservation of matter
      answer
      matter can't be created or destroyed
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      mass number
      answer
      protons + neutrons
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      mega
      answer
      106
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      micro
      answer

      10-6

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      mixtures
      answer

       

      • when two or more substances combine & retain individual properties
      • physical blends of pure substances
      • retain the properties of materials used in the mixture
      • easily separated 

       

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      nano
      answer
      10-9
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      neutrons
      answer

      • negatively charged
      • found in nucleus
      • contributes to mass of an atoms

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      nonrenewable resources
      answer
      cannot be replenished, ex:petroleum
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      protons
      answer

      • positive charge
      • equal to atomic number

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      pure substances
      answer

       

      • atoms chemically combine or stand alone
      • get new properties when made
      • hard to break apart

       

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      resin
      answer

      • provides the desirable protective properties
      • used in coating

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      solubility
      answer

       

      • amount of solute dissolved in amount of solvent at a given temperature
      • concentrated- more solute than solvent
      • diluted- more solvent than solute
      • unsaturated- has not reached limit
      • saturated- limit has been reached
      • supersaturated- gone above the threshold
      • as temp increases, solubility increases (except gasses, temp increases and solubility decreases)

       

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      solution
      answer

       

      • homogenous
      • solvent- does the dissolving
      • solute- being disolved

       

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      subscripts
      answer
      identifies # of atoms present
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      theory
      answer
      an explanation of the behavior, can be wrong
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