Regents Chemistry Mid-year Exam
Periods 3 & 8 – Wednesday, Jan. 20, 2010
Periods 1 & 6 – Thursday, Jan. 21, 2010
(Bring a scientific calculator)
SchoolIsland Bonus Quiz – due Tuesday, Jan. 19th, 8 AM.
After school review – 2:40 PM, Tuesday, 1/19/08
Study Guide
- Matter and Energy
- Matter is anything that has mass and volume
- Types of matter
- Pure substances (one set of properties – can’t be separated by physical means)
- Elements
- Compounds
- Mixtures (two or more sets of properties – can be separated by physical means)
- homogeneous – uniform throughout
- heterogeneous – not uniform, “chunky”
- Differences in properties and structures
- Changes
- Physical changes – do not change the identity of a substance (example: phase changes)
- Chemical changes – form a new substance
- Energy – the ability to do work
- Kinetic energy – the energy of motion
- measured by temperature
- Calculations (Heat = mass x sp. heat x change in temp)
- Potential energy – the energy of position
- energy involved in phase changes (molecules change their position relative to one another
- Calculations
- melting/freezing – Heat = mass x Heat of Fusion
- boiling/condensing – Heat = mass x Heat of Vaporization
- Atomic Structure
- Development of the Atomic Theory
- John Dalton
- JJ Thompson
- Experiments with cathode ray tubes
- Discovered electron
- plum pudding/chocolate chip cookie model of the atom
- Ernest Rutherford
- Gold foil experiment
- Discovered the nucleus
- Atom is mostly empty space
- Niels Bohr
- Explained bright line spectrum of hydrogen
- electrons are in definite energy levels/orbits in the outer part of the atom.
- Electrons can jump from a lower energy level (ground state) to a higher energy level (excited state) with the addition of energy.
- Electrons give off energy as photons of light as they fall from higher energy levels to lower ones.
- Quantum mechanical/wave mechanical model of the atom
- Electrons are located in orbitals rather than orbits.
- Orbitals are areas of high probability of locating an electron within the atom.
- Definitions
- Protons, neutrons, electrons, nucleus
- Mass number
- Atomic number
- Average atomic mass
- Isotopes
- Calculation of ave. atomic mass given the mass of the isotopes and their relative abundance in nature.
- Each radioactive isotope has a unique half-life and decay mode that can be found in Table N.
- Periodic Table
- History
- Developed by Mendeleev based on chemical/physical properties and atomic mass
- Modern table is based on chemical/physical properties and atomic number
- Parts of the Periodic Table
- Periods – rows in the Periodic Table
- Groups/Families – columns in the Periodic Table. The elements in the same group share similar chemical and physical properties.
- Alkali metals – Group 1
- Alkali earth metals – Group 2
- Halogens – Group 17
- Noble gases – Group 18
- Metals – located to the left of the “Mason-Dixon” line – lose electrons in chemical reactions
- Non-metals – located to the right of the “Mason-Dixon” line – gain electrons in chemical reactions
- Metalloids/Semi-metals – adjacent to the “Mason-Dixon” line – can gain or lose electrons in chemical reactions.
- Transition metals – Groups 3 – 12 (tend to form colored compounds)
- Rare earth elements
- Lanthanide and actinide series
- Periodic Table and electron structure
- Elements in the same group have the same number of valence electrons (electrons in the outermost energy level).
- Elements in the same period have their valence electrons in the same energy level.
- Trends in the Periodic Table
- Metallic character – decreases as you go across a Period and increases as you go down a Group.
- Ionization energy – (energy required to remove the outermost electron) increases as you go across a Period and decreases as you go down a Group.
- Atomic radius – decreases as you go across a Period and increases as you go down a Group.
- Electronegativity – (the measure of an atoms ability to attract electrons in a bond) increases as you go across a Period and decreases as you go down a Group.
- Bonding
- Energy is released when bonds form and energy is required to break bonds.
- Ionic
- Results from the transfer of electrons
- Metal atoms lose electrons to form positive ions (cations)
- The charge on the metal ion is determined by the number of electrons that are lost.
- Group 1 (alkali metals) lose 1 valence electron to form 1+ ions
- Group 2 (alkali earth metals) lose 2 valence electrons to form 2+ ions
- Transition metals tend to form more than 1 type of ion. The charge on the ion is indicated by a Roman numeral. (Iron (III) is Fe 3+)
- Non-metal atoms gain electrons to form negative ions (anions)
- Non-metal atoms tend to gain enough electrons to get 8 electrons in their valence shell (Example: Oxygen atoms, with 6 valence electrons, tend to gain 2 electrons and form ions with a charge of 2-)
- Positive and negative ions are held together by the electric force.
- Formula Writing
- The sum of the positive and negative charges on the ions in a compound must always add up to zero.
- Negative ions
- Monatomic – end in ide
- Polyatomic – end in ate or ite (Table E)
- Do NOT use prefixes.
- Covalent
- Usually occur between two non-metallic elements
- Result from the sharing of valence electrons.
- Result in the formation of molecules, rather than ions
- Usually follow octet rule (bond to get 8 electrons in outermost shell)
- Formula writing
- Utilize prefixes to indicate the number of atoms in a molecule (mono, di, tri, tetra )
- Lewis Diagrams (Electron Dot Diagrams)
- Draw diagrams for neutral atoms, ions, ionic compounds, covalent compounds.
List of Required Calculations on next page.
Required calculations/measurement concepts
- Significant figures
- Determining the number of sig figs in a measurement (Atlantic-Pacific Rule)
- Read a measurement device to the correct number of sig figs.
- Using sig figs in calculations
- Density = mass/volume
- Conversions
- liters to milliliters, milliliters to liters
- meters to centimeters, centimeters to meters
- Energy
- Change in temperature ( Heat = mass x sp. heat x change in temp)
- Change in phase
- melting/freezing – Heat = mass x Heat of Fusion
- boiling/condensing – Heat = mass x Heat of Vaporization
- Average atomic mass - Calculation of ave. atomic mass given the mass of the isotopes and their relative abundance in nature.
- Formula mass – the sum of the atomic masses of the atoms that make up the formula (example: the formula mass of H2O is 18 amu)
- Moles
- Determine molar mass
- Convert grams to moles
- Convert moles to grams
- Percent composition