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Midterm
Chem Midterm Review
92
Chemistry
11th Grade
01/16/2010

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Term
% Compostition
Definition

  • 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

Term
% concentration by mass
Definition

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

Term
Accuracy
Definition
the average of data
Term
Acids
Definition

  • H as cation
  • sour 
  • react with metals

Term
Activity Series
Definition

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

 

Term
Allotropes
Definition

  • 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 

Term
Alloy
Definition

  • 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 

Term
Anode
Definition

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

Term
Atom Interaction
Definition

  • 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

Term
Bases
Definition

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

Term
Boiling Point
Definition

 

  • 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

 

Term
Cathode
Definition

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

Term
Chemical Change
Definition

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

Term
Coatings
Definition


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

    • heterogenous
    • suspended material

    Term
    Covalent Bonds
    Definition

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

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

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

    Term
    Electrode
    Definition

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

    Term
    Groups/Families
    Definition

    • 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

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

    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

    Term
    Kelvin
    Definition
    degrees celsius + 273.15
    Term
    Life Cycle of a Material
    Definition

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

    Term
    Matter
    Definition
    anything that has volume and mass
    Term
    Mineral
    Definition

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

    Term
    Mixtures
    Definition

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

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

    • 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

    Term
    Mole
    Definition

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

    Term
    New Periodic Table
    Definition

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

    Term
    Nitrogen Family
    Definition
    bonds with other elements the most
    Term
    O in Oxide
    Definition

    • same amounts in elements of the same family

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

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

    Term
    Oxidation Reduction Reactions (Redox Rxns)
    Definition

    • 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

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

    • used in coatings
    • provides color

    Term
    Plating
    Definition

    • 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

    Term
    Powder Coating
    Definition

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

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

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

    Term
    Properties of nonmetals
    Definition

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

    Term
    Pure Substances
    Definition

     

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

     

    Term
    Reactivity trend on the Periodic Table
    Definition

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

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

    • 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 

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

    • 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

    Term
    Semiconductors
    Definition

    • 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

    Term
    Significant Digits
    Definition

    • 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

    Term
    Solvent
    Definition

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

    Term
    Solvent
    Definition

    • used in coating
    • allows application in liquid form

    Term
    Supply and Demand
    Definition

    • 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

    Term
    Suspension
    Definition

    • heterogenous
    • material settles out

    Term
    Thin Films
    Definition

    • 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

    Term
    Tyndall Effect
    Definition

    lights scattered by solids, shows colloids

    Term
    Waste Management
    Definition

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

    Term
    Ways to separate mixtures
    Definition

     

    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

     

    Term
    Where is the Earth's Water?
    Definition

    • 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

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

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

    Term
    density
    Definition

    • mass/volume
    • on a graph density=slop

    Term
    dimensional analysis
    Definition

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

    Term
    electrons
    Definition

     

    • 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

     

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

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

    Term
    heavy metal ions
    Definition

     

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

     

    Term
    ion
    Definition

     

    • 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

     

    Term
    ionic compound
    Definition

     

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

     

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

    10-6

    Term
    mixtures
    Definition

     

    • 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 

     

    Term
    nano
    Definition
    10-9
    Term
    neutrons
    Definition

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

    Term
    nonrenewable resources
    Definition
    cannot be replenished, ex:petroleum
    Term
    protons
    Definition

    • positive charge
    • equal to atomic number

    Term
    pure substances
    Definition

     

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

     

    Term
    resin
    Definition

    • provides the desirable protective properties
    • used in coating

    Term
    solubility
    Definition

     

    • 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)

     

    Term
    solution
    Definition

     

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

     

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