C

Chem Notes 1&2

  • Heterogeneous Mixture – a mixture that is not the same throughout.

  • Homogeneous Mixture (Solution) – a mixture that is the same

  • throughout.

  • Physical Properties: can be measured or observed w/o changing the composition or identity of the substance

    • Density, conductivity, melting point, color, hardness

  • Chemical Properties: describe the way a substance may change or react to form other substances

    • Flammability, corrosivity, reactivity

  • Chemical reactions occur during chemical changes

  • Chapter 2

    • Electron is lightest particle (basically weightless)

    • 1c/s=1a

      • One coulomb of electric charge flows through a conductor in one second is equivalent to one ampere of electric current

    • In periodic table, elements are arranged in order of increasing number of protons

      • Not all elements have same neutrons/protons, so elements are arranged with protons

        • Hydrogen has 1 proton but no neutrons bc it doesn’t require a neutron, but helium has 2 of each

        • Isotope has same number of protons but different number of neutrons

    • Atomic Symbols

      • Mass Number   A=# protons and neutrons (A=p^+ + n0)

      • Atomic Number   Z = # protons (p^+)

      • In neutral atom the # electrons (e^-)= # of protons (p+)

      • ^48Ti

        • Protons= 22

        • Neutrons=26 (48-22)

        • Electrons=22

    • Ions

      • When neutral atoms lose or gain electrons, they become ions

        • Cations are positive and are usually formed by metals (Mg2+) (losing 2 electrons)

        • Anions are negative and are usually formed by non-metals (O^2-) (gaining 2 electrons)

      • ^51V^4+

        • P= 23

        • N= 28 (51-23)

        • E= 19 (23-4)

    • Isotopes

      • Atoms w/ the same # protons (atomic #) different # of neutrons (mass number). Some isotopes are more abundant than others

    • Mass Spectrometry

      • Ionized isotopes are separated due to differences in their mass to charge ratio. The relative abundances can be calculated using this method

    • Atomic weights

      • Elements with lower potential energy are higher stabilized

      • amu=atomic mass=weighted avg of all isotopes

        • DEPENDS ON ABUNDANCE

        • Don't add both mass and divide if diff abundance

  • Periodic Table

    • Rows are called periods

    • Columns are called groups

      • 1A: Alkali metals (disclude H)

      • 2A: Alkaline earth meals

      • 6A: Chalcogens

      • 7A: Halogens

      • 8A: Noble gases

    • There are metals, metaloids, and non-metals

  • Chemical Compounds

    • Ionic compounds formed between cations and anions (e.g. metal cation + nonmetal anion)

    • Covalent compounds formed between nonmetal atoms (nonmetal + nonmetal)

  • Chemical formulas

    • Empirical formula-simplest whole-number ratio of atoms of eac helmet in a compound. Ionic compounds always have empirical formulas

    • Molecular formula-exact number of atoms of each element in an individual molecule. Covalent compounds have molecular formulas

    • Structural formula-exact connectivity of the atoms

  • Naming oxyanions

    • -ate (sub thing more than -ite)

      • Sulfate (SO4-)

    • -ite (sub thing less than -ate)

      • Sulfite (SO3-)

    • If anion is an element, change its ending to -ide; if the anion is a polyatomic ino, simply write the name of the polyatomic atom (NaNO2 - Sodium Nitrite) (NaF - Sodium Fluoride)

      • FeCl2 - Iron (II) Chlorite

      • Fe(NO2)3 - Iron (III) Nitrite

      • NH4*+ S*2-  =  (NH4)2S

  • When combining elements/compounds, but the exponent by the other compound and have them swap then do smallest ratio

  • Nickel (II) Cyanide = Ni*2+ CN*-  =  Ni(CN)2

  • Naming covalent compounds

    • Acid - H+ & an anion

      • H2CO3 carbonic acid

      • Hydrogen containing covalently bonded compounds that give off H+ in water (acids are non ionic compounds)

      • Naming acids

        • ___ide → (add H+ ions) hydrofluoric acid (HF) (Binary acid)

        • ___ate → (add H+ ions) Nitric acid (HNO3) (Oxyacid)

        • ___ite → (add H+ ions) Nitrous acid (HNO2) (Oxyacid)

      • Naming binary covalent bonds

        • A prefix (mono, di, tri, etc) is used to denote the # of atoms of each element in the compound (mono- is not used on the first element listed, however)

          • CO2- 

          • Carbon dioxide

          • N2O5- Dinitrogen pentaoxide

    • Inorganic - non-metal + non-metal

      • CO2 carbon dioxide

    • Organic - CnHm

      • C3H8 propane