Midterm

% Compostition

  • 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

% concentration by mass

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

Accuracy
the average of data
Acids

  • H as cation
  • sour 
  • react with metals

Activity Series

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

 

Allotropes

  • 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 

Alloy

  • 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 

Anode

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

Atom Interaction

  • 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

Bases

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

Boiling Point

 

  • 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

 

Cathode

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

Chemical Change

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

Coatings


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

    • heterogenous
    • suspended material

    Covalent Bonds

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

    Demetri Mendeleev
    father of the periodic table
    Doping
    adding impurities to pure forms of semiconductors in order to increase their conductive properties
    Earth’s Compostition

    • atmosphere- air
    • hydrosphere- water
    • lithosphere- earth
    • crust- top layer of earth, solid
    • mantel- (Mg and Fe), fluid like
    • Core- (Fe and Ni), solid

    Electrode

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

    Groups/Families

    • 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

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

    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

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

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

    Matter
    anything that has volume and mass
    Mineral

    • solid compounds containing the element or group of elements of interest
    • found in ore

    Mixtures

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

    Modifying Properties
    Can be modified by synthesizing material with other elements or compounds at molecular level
    Molar Mass

    • 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

    Mole

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

    New Periodic Table

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

    Nitrogen;Family
    bonds with other elements the most
    O in Oxide

    • same amounts in elements of the same family

    Ore
    naturally;occurring;rock or mineral that can be mined and from which it is profitable to extract metal or other material
    Original Periodic Table

    • based on atomic mass
    • worked well for light elements but isotopes caused problems

    Oxidation Reduction Reactions (Redox Rxns)

    • 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

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

    • used in coatings
    • provides color

    Plating

    • 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

    Powder Coating

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

    Precision;
    reproducible;results
    Properties of Metalloids
    mix between properties of metals and nonmetals
    Properties of Metals

    • malleable
    • shiny/metallic luster
    • conduct
    • very reactive w/ acids
    • reacts w. CuCl2

    Properties of nonmetals

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

    Pure Substances

    ;

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

      Reactivity trend on the Periodic Table

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

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

      • 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;

      Renewable Resources
      can eventually be replenished through natural or artificial process, ex: food or lumber
      Rows/Periods
      horizontal rows on the periodic table
      Rules of Balancing Equations

      • 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

      Semiconductors

      • 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

      Significant Digits

      • 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

      Solvent

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

      Solvent

      • used in coating
      • allows application in liquid form

      Supply and Demand

      • 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

      Suspension

      • heterogenous
      • material settles out

      Thin Films

      • 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

      Tyndall Effect

      lights scattered by solids, shows colloids

      Waste Management

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

      Ways to separate mixtures

      ;

      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

      ;

      Where is the Earth’s Water?

      • 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

      Why were gold, silver, and copper the first metals to be discovered?
      they are chemically inert, and found in their free state in nature
      charge
      protons – electrons
      chemical symbols
      represent identity of an atom
      covalent compounds

      • dissolve down to molecules
      • can have partial charges= polar covalent
      • ionic substance do not dissolve in non-polar covalent

      density

      • mass/volume
      • on a graph density=slop

      dimensional analysis

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

      electrons

      ;

      • 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

      ;

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

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

      heavy metal ions

       

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

       

      ion

       

      • 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

       

      ionic compound

       

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

       

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

      10-6

      mixtures

       

      • 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 

       

      nano
      10-9
      neutrons

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

      nonrenewable resources
      cannot be replenished, ex:petroleum
      protons

      • positive charge
      • equal to atomic number

      pure substances

       

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

       

      resin

      • provides the desirable protective properties
      • used in coating

      solubility

       

      • 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)

       

      solution

       

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

       

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

      Hi!
      I'm Larry

      Hi there, would you like to get such a paper? How about receiving a customized one?

      Check it out