Midterm Exam Review, 2016

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1 Midterm Exam Review, 2016 Name: Period/Teacher: I. Unit 1, Safety in the Lab For the most part, assume that this unit is pretty much common sense. Be able to identify lab equipment by picture and know what to use when measuring mass, volume, etc. A few not-so-obvious reminders: Always report accidents in the lab, no matter how small they appear. Follow your procedure or verbal directions for chemical disposal. NEVER assume it can go in the trash or down the sink. The sewer rats below the school are huge and already quite radioactive. Chemicals are never returned to their containers after use. Refer to proper disposal directions. Acid + water = heat. Always add acids to water, other way = sizzle...sizzle...boom! Test tubes = mini-bazookas, act accordingly. (No target practice, no matter how much your lab partners annoy you.) Safety diamonds read from = virtually no risk and 4 = extreme hazard. o Blue = health // Red = fire and flammability // Yellow = reactivity // White = special hazards. II. Unit 2, Matter and Change A. Classifying Matter: matter is classified into 4 different types as shown below: i. Element: a pure substance made of only one type of atom. Ex. Fe, O 2, U... ii. Compound: two or more different elements chemically-bonded to one another. Ex. H 2 O, NaCl iii. Homogeneous Mixtures: a physical combination which is so well mixed that it appears to be pure. Ex. salt water = NaCl + water / Air = N 2 + O 2 + CO 2 + Ar + H 2 O. iv. Heterogeneous Mixtures: physical combinations of matter which are obviously made of different materials. Ex. Pizza, salad, you (humans!)

Chemical changes actually create something NEW. Substance A becomes substance B.

2 Classify the substances shown to the left: A = B = C = D = B. Differentiating Between Physical and Chemical Changes: i. Chemical changes actually create something NEW. Substance A becomes substance B. Anything else is considered physical. Burning Rotting Chopping Melting Boiling Subliming Rusting Freezing Reacting Condensing Cutting Digesting

3 C. Chemical, Physical, Intensive, and Extensive Properties: i. Chemical and physical properties can be differentiated by how they are tested. Testing chemical properties changes a substance or otherwise destroys the material being tested. Physical properties can be tested without this happening. ii. Intensive properties are based on what a substance IS, while extensive properties changes depending on HOW MUCH of a substance you have. Flammability Viscosity Conductivity Magnetism Mass Luster Volume Density Reactivity Ionization Energy Electronegativity Length Toxicity Melting Point Temperature Boiling Point D. States of Matter: i. Solids, liquids, gases, and plasmas:

4 III. Unit 3, Atomic Structure and the Periodic Table: A. Isotopes and Average Atomic Masses: i. Remember, all atoms of an element have the same number of protons, but not necessarily the same number of neutrons. As a result, there can be many different types of the same element called isotopes. These are named according to mass: Carbon-12, Carbon-13, Carbon ii. Complete the example below: If carbon is 68.1% 12 C, 9.3% 13 C, and 22.6% 14 C, calculate the average atomic mass. (Follow the steps below.) 1. Convert the percent abundance of each isotope into decimal form: 2. Mutliply these decimals by their respective masses: 3. Add it all up: iii. Your turn: Given that silver is 0.9% silver-109, 30.7% silver-107, and 68.4% silver-108, calculate the average atomic mass of this element.

5 B. Scientists and their Discoveries: Dalton Thomson Rutherford Bohr Schrodinger Mendeleev Moseley C. Groups, Periods, Properties of the Elements, Valence Electrons, and Families:

6 i. Notable Families: 1. Alkali Metals: Group 1, VERY reactive, especially with water. 2. Alkaline Earth Metals: Group 2, fairly reactive. 3. Halogens, Group 17, most reactive among the non-metals. 4. Noble Gases, Group 18, non-reactive, completely stable. D. Trends and Patterns in Reactivity: i. Electronegativity: "power" to take electrons from another element. ATTACK! ii. Ionization Energy: amount of energy required to remove an electron. DEFENSE! iii. Atomic Radius: distance between the nucleus and the edge of the electron cloud. SIZE! iv. Reactivity: how likely an element is to undergo a chemical change. DO STUFF! E. E-M Radiation (Light): i. Light is the fastest object in the known universe at a speed of 3.00e8 m/s in a vacuum (outer space). We abbreviate this as "c" in mathematical equations. Light is often described in terms of wavelength, frequency, and energy:

7 Wavelength and Frequency: Energy and Frequency: Energy and Wavelength: ii. Calculating wavelength, λ and frequency, f: c = λ f f = λ = iii. Dealing with nanometers: nanometers / 1e9 = meters meters 1e9 = nanometers, nm Ex.1) A photon of light has a wavelength of 42 nm, what is its frequency?

8 Ex.2) What is the wavelength of light, in nm, with a frequency of 4.3e12 Hz? iv. Calculating the energy of light: E = h f h = 6.626e-34 Planck's Constant) E = h c / λ Ex.3) The ionization energy of a single atom of sodium is 8.3e-19 J. What is the minimum frequency of light necessary to remove an electron from a sodium atom? Ex.4) Orange light has a wavelength of 605 nm. What is the energy of this specific color of light? Ex.5) A xenon difluoride laser emits a photon of light whose energy is measured to be 4.5e-15 J. What is the wavelength, in nm, of this photon?

9 IV. Unit 4, Chemical Bonding and Electron Configurations A. Writing Electron Configurations: Ex.1) Nitrogen, N Ex.2) Sodium, Na Ex.3) Yttrium, Y Ex.4) Silver, Ag Ex.5) Uranium, U B. Types of Chemical Bonds: i. Covalent: Non-Metal/Non-Metal - share electrons, represented by a line in Lewis diagrams. H O C O H C H H

10 ii. Ionic: Metal/Non-metal - electrons are given and taken. Shown by charges in Lewis diagrams. Na Cl F Ca F iii. Metallic: Metal/Metal (alloys and pure metals) - mobile electrons in a "sea" around the nuclei. Au Au Au Au Cu Zn Cu Zn Au Au Au Au Zn Cu Zn Cu C. Drawing Lewis Dot Diagrams: i. For single atoms or ions: determine the number of valence and, starting at the top of the atom/ion's symbol, place them clockwise one at a time: O O 2- Al Al 2+ ii. Compounds require several more steps: 1. Find the total number of valence electrons. 2. Least electronegative element in center. Always C, never G1. 3. Covalent- draw single bonds (2 electrons each). Skip to 4 if ionic. 4. "Feed" most electronegative elements (most = 8, H=2, B=6) 5. If covalent- out of electrons and atoms are still not "happy"? Build double or triple bonds. If Ionic - assign charges by comparing starting electrons to ending electrons. More = -, less = +. Ex.1) H 2 O Ex.2) NaF

11 Ex.3) CHCl 3 Ex.4) MgO Ex.5) CO 2 Ex.6) CO 3 2- D. Molecular Geometries (VSEPR and shapes): i. Use AXE method to determine the shapes of molecules.

12 Ex.1) Determine the shape of the ammonia molecule, NH 3 : Ex.2) What is the molecular geometry of sulfur difluoride? V. Unit 5, Chemical Nomenclature: A. Covalent Naming: i. General Pattern: Prefix + name prefix + stem-ide Ex.1) C 2 O Ex.2) C 3 H 8 Ex.3) P 4 S 6 Ex.4) As 5 Cl 10 Ex.5) Heptiodine nonoxide Ex.6) Trichlorine tetrafluoride B. Ionic Naming: i. General pattern: metal name + non-metal stem-ide ii. Use "swap and drop" for this and all non-covalent formulas! Simplify as needed. Ex.1) NaBr Ex.2) CaO

13 Ex.3) potassium fluoride Ex.4) aluminum nitride iii. All metals outside of groups 1, 2, and 13 require roman numerals in their names! Ex.5) PbO Ex.6) AuCl 4 Ex.7) vanadium (III) sulfide Ex.8) iron (I) oxide C. Polyatomic Naming: i. Follow all the same rules for ionics BUT do not change the name of the poly in any way. ii. Log on to chemhelp.us and the REF/Calculator tab to access a formula chart. FYI - you'll have the formula chart on the exam. Ex.1) NaOH Ex.2) Cu(NO 2 ) 2 Ex.3) Li 3 PO 4 Ex.4) (NH 4 ) 2 S Ex.5) barium sulfate Ex.6) potassium perchlorate Ex.7) sodium dichromate Ex.8) ammonium chromate

14 D. Acid Naming: i. Binary acids (H-Halogen): hydro-halogen stem-ic acid ii. Polyatomic acids (H x -Poly): 1. If poly ends in -ate, poly stem-ic acid 2. If poly ends in -ite, poly stem-ous acid Ex.1) HBr Ex.2) H 2 CO 3 Ex.3) chromic acid Ex.4) hydrofluoric acid Ex.5) phosphoric acid Ex.6) nitrous acid Ex.7) HNO 3 Ex.8) HCl You have finally reached the end of this review. Trying to sum up everything you've learned over the last 3.5 months is quite a challenge, but you've done it. You're ready for the mid-term exam. If you've completed all of this review and made 100s on the online practice sets, you can take the mid-term with little worrythe exam will be easy and you can enjoy a nice long break as your reward. No further studying is required. Rest and come ready to rock on Thursday and Friday! FIN (until next semester)

Chemistry CRT Study Guide First Quarter

Chemistry CRT Study Guide First Quarter Number AL COS # 1. #1.0 Classify sodium chloride as an element, mixture, compound, or colloid. Compound 2. #1.0 Classify air as an element, mixture, compound, or colloid. Mixture 3. #1.0 Classify a blueberry