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Chemistry 2A Review

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  • Name the molecular compound: N2O5
    Dinitrogen pentoxide
  • What is the formula for percent yield?
    Actual yeild / theoretical yield = as a percent
  • What geometric shape results from a central atom that is bonded to two other atoms and has a single lone pair?
    Planar trigonal
  • Does hydride, H(-1) have a noble gas configuration? Why?
    Yes [He]. It has a full valence shell: since only two electrons can fill an s orbital, the addition of a single electron to hydrogen matches the noble gas He.
  • Name the ion: Na2SO4
    Sodium sulfate
  • When naming transition metal ions, what do the Roman numerals represent? (Ex. Silver(II) )
    Represents the charge on the ion
  • What is the charge on a nitrite ion? What ion would bond to one nitrite ion? What's the formula
    Charge: -1. Ex. Na+ : NaNO2
  • How do you determine the charge cloud of a molecule? What does the charge cloud of HCl look like?
    Look at the lone pairs on each atom. Chlorine has three lone pairs making it more negatively charged. Hydrogen has no lone pairs, so it's positively charged.
  • Why do some elements "disobey" the octet rule when forming bonds in covalent compounds?
    Pairing electrons can fill the d orbital(s) and thus form more bonds than allowed by the valence shell.
  • Where does the value of the actual yield come from?
    Experiments
  • Is Li2SO4 soluble?
    Yes
  • What is another name for an acid-base reaction?
    Neutralization reaction
  • What ions are released by acids and bases respectively?
    Hydronium and hydroxide ions
  • How can you recognize a precipitation reaction?
    A solid and an aqueous solution will be formed by the reaction of two aqueous solutions
  • What is the oxidation number of oxygen in NaOH?
    -2
  • How do you find the molecular weight of CH4? What is that value?
    Add up the atomic weights of all atoms in the molecule. CH4 ~ 16g/mol
  • The reaction between CuCl2 and Hg(ClO4) will form what products? What are their solubilities?
    Cu(ClO4)2: Aqueous HgCl: Solid
  • Why can an element assume the configuration of a noble gas without actually being a noble gas? What allows the element to retain its identity?
    Only the number of electrons change the configuration, but the number of protons in the nucleus determines the identity.
  • How many bonds does carbon like to form in covalent molecules?
    4 bonds
  • Covalent compounds are most known for what physical property?
    Low melting/boiling points
  • Name the ion: KI
    Potassium Iodide
  • What's the formula for a nitrite ion?
    NO3 (-2)
  • What are the three types of chemical reactions?
    Acid-base neut., redox, precipitation
  • What do we mean by saying a chemical equation has "no reaction"?
    When products are not actually formed, but momentarily combined and separated again. Ex. two aqueous solutions produce two different aqueous solutions
  • How can you recognize an acid-base reaction given the chemical equation?
    An acid and a base will be in the reactants (look for H on one and OH on the other) and water will be a product
  • How do we find the theoretical yield of a reaction?
    Gram-mole conversions using the balanced reaction and the amount of reactant(s) used.
  • What geometric shape results from a central atom that is bonded to a single atom and has three lone pairs?
    Linear
  • Why does a chemical reaction have to be balanced before it can be used for any computation?
    Law of Conservation of Mass
  • Why do lone pairs on a central atom change the geometric shape of the molecule?
    The lone pairs are a repulsive force against the electrons surrounding other atoms bonded to the central atom, thus changing the bond angles
  • How many bonds does nitrogen like to form in covalent molecules?
    3 bonds
  • What's the difference between ions and molecules?
    Ions are formed when electrons are transferred and atoms are attracted by charge. Molecules are formed when atoms share electrons in different types of bonds.
  • How many bonds does oxygen like to form in covalent molecules?
    2 bonds
  • Based on their Lewis structures, what is the difference in bonding between a carbon dioxide molecule and a carbonate ion?
    Carbonate has a double bond & lone pair on carbon. Carbon dioxide has two double bonds.
  • What is the formula for silver cyanide?
    AgCN
  • What is the charge of iron in FeCl2? What's the name of this compound?
    Charge: +2. Iron(II) chloride
  • Name the following compound: Na2SO4
    Sodium sulfate
  • Name the compound: TiCl4
    Titanium tetrachloride