CP Chemistry
Final Exam Review Sheet Fall 2010 ANSWER KEY
The multiple choice final exam is 15% of your overall final grade. To study for the multiple choice portion, it is suggested you use this review sheet, your notes, AKS log book, handouts, textbook, and labs. On the day of the exam, you will need to bring a #2 pencil and a calculator. A periodic table will be provided for you.
Lab Equipment/Safety1. a) What is a hypothesis? testable, refutable explanation for an observation or a problem
b) What is a theory? A hypothesis that has been supported by repeated experiments
c) What is a law? it describes relationships in nature without exception
2. What is the difference between accuracy and precision? Accuracy means that the measurements made are correctly (they are very close to the accepted measurement). Precision means that a series of measurements are close to each other (you can make the same measurement more than once and get about the same measurement each time). Note: measurements can be precise and not accurate.
Measurement and Matter3. Use the data table below to discern whether the students’ measurements are accurate only, precise only, both accurate and precise, or neither accurate nor precise.
Measurement 1 / Measurement 2 / Measurement 3 / Measurement 4Jameel / 5.0 g / 4.9 g / 5.0 g / 5.1 g
Cody / 8.0 g / 8.2 g / 8.0 g / 7.9 g
Rachel / 2.0 g / 12.0 g / 8.0 g / 20.0 g
Juan / 10.0 g / 9.9 g / 10.1 g / 9.9 g
****The accepted value of the rock’s mass is 5.0 g
a) Describe Jameel’s measurements. accurate & precise
b) Describe Cody’s measurements. precise
c) Describe Rachel’s measurements. neither
d) Describe Juan’s measurements. precise
4. a) What piece of lab equipment measures mass? electronic balance
b) What piece of lab equipment most accurately measures volume of a liquid? graduated cylinder
c) What is the SI unit to measure length? meter Mass? gram
5. a) What is the formula for density? D= m/v (density = mass/volume)
6. a) How is the volume of a regularly-shaped object, such as a box or book, found? v = length x width x height
b) What is the name for the method by which the volume of an irregularly-shaped object is found?
water displacement method (subtract the final volume from the initial volume: V = Vfinal – Vinitial)
7. Calculate the density of an object with a volume of 25 cm3 and a mass of 50. g.
D = m/v D = 50. g = 2.0 g/cm3
D = ? 25 cm3
m = 50. g
v = 25 cm3
8. The volume of water in a graduated cylinder rose from 52.2 mL to 56.2 mL when a solid object was placed in the water. If the mass of the object is 38.6 g, what is the density of the object?
D = m/v D = 38.6 g = 9.65 g/mL
D = ? 4.00 mL
m = 38.6 g
v = 4.00 mL
v = vfinal - vinitial
v = 56.2 mL – 54.2 mL = 4.00 mL
9. You are making a density column in a graduated cylinder with vegetable oil, honey, lamp oil, and water. Layer the order of liquids that you would have in the density column from top to bottom. The following chart lists the densities of each substance.
Liquid / DensityVegetable Oil / 0.91 g/mL
Honey / 1.36 g/mL
Lamp Oil / 0.80 g/mL
Water / 1.00 g/mL
Lamp oil, vegetable oil, water, & honey
10. Matter is anything with mass and volume.
11. a) Which state/phase of matter is described as being tightly packed and highly organized with particles vibrating back and forth? solid
b) Which state/phase of matter is described as having disorganized particles as far apart as possible with a high degree of kinetic energy? gas
c) Which state/phase of matter is described as having particles that are relatively close together and “flow” while taking the shape of the container? liquid
12. a) Fill in the blanks in the data table below.
Description / Physical or Chemical Change? / State/PhaseInvolved in Change? / Does Kinetic Energy Increase or Decrease?
water boils / physical / liquid to gas / increase
ice melts / physical / solid to liquid / increase
water vapor condenses / physical / gas to liquid / decrease
iodine crystals sublime / physical / solid to gas / increase
13. a) A mixture that is uniform throughout is classified as a homogeneous mixture whereas a mixture that is not uniform in appearance is known as a heterogeneous mixture.
14. Fill in the chart below listing the physical properties of each type of mixture:
Mixture Type / Appearance/Particle Size / Heterogeneous or Homogeneous? / Tyndall Effect Positive or Negative? / Is there Settling?Suspension / largest particles; visible with naked eye / heterogeneous / Positive – light beam IS visible in mixture / settles into layers
Colloid / intermediate (medium) sized – not visible with naked eye without Tyndall Effect test / heterogeneous / Positive – light beam IS visible in mixture / no settling
Solution / smallest size particles – not visible with naked eye / homogeneous / Negative – light beam NOT visible in mixture / no settling
15. a) A cloudy mixture with no settling, and a positive Tyndall effect would be classified as a(n) colliod.
b) On the other hand, a mixture with no settling, no visible layers, and a negative Tyndall effect would be classified as a(n) solution.
16) If a cough medicine reads “shake before using,” it is probably what specific type of heterogeneous mixture? Suspension; it settled into layers so to “mix” the layers, you need to shake the mixture. Italian salad dressing is also a good example of a suspension because you have to shake it before pouring it onto a salad.
17. a) A type of homogeneous mixture made of two or more metals melted together is known as a(n) alloy.
b) An example of this would be brass because it is made of copper and zinc.
18. Identify the following as a chemical or physical.
a. copper reacts with oxygen to form a green patina chemical change (new substance green patina & color change)
b. milk spoils chemical change (milk altered – you wouldn’t drink spoiled milk!)
c. copper compounds are blue physical property (observation of color – color did not change)
d. water evaporates on a hot summer day physical change (changed from liquid to gas)
e. ice melts if not in the freezer physical change (changed from solid to liquid)
f. fermentation of grapes to make wine chemical change (new substance wine)
g. an iron nail rusts chemical change (new substance rust)
h. combustion of wood chemical change (made CO2 and H2O)
i. state of matter changes physical change (only changed how far apart atoms are)
j. dissolving of chocolate in milk physical change (can separate chocolate from milk)
19. What are four pieces of evidence that a chemical change is taking place?
color change gas forms (smoke, bubbles)
precipitate formation odor change
temperature change
20. Indicate whether the following can be separated by physical, chemical, or nuclear means.
a) atoms nuclear
b) compounds chemical
c) mixtures physical
Atomic Structure21. a) Define the term atom in your own words (do not copy the definition from the book)! An atom is the
smallest particle of an element that retains the properties of that element (still has the same boiling
point, density, etc.)
b) The atomic number of an element is based on which subatomic particle? proton
c) Which element has atomic number 8? oxygen
d) In a neutral atom, the number of protons is equal to the number of electrons.
22. Fill in the chart below concerning subatomic particles.
Subatomic Particle / Location / Charge / Job of Particleproton / Nucleus / +1 / Identifies the element
neutron / in nucleus / 0 (neutral – no charge) / determines isotopes of an element
electron / outside nucleus in electron cloud / negative / determines chemical reactivity (which elements bond together to get a full octet)
23. a) The majority of the mass of the atom is in which part of the atom? nucleus
b) The mass number is equal to the number of protons and neutrons added together. This is because the mass of the atom is in the nucleus and the protons and neutrons are in the nucleus.
c) An atom with 11 protons, 12 neutrons, and 11 electrons would have a mass number of 23 (protons + neutrons).
d) An atom with 11 protons, 12 neutrons, and 11 electrons would have an atomic number of 11 (# protons).
e) What would be the isotopic notation for an atom with 11 protons, 12 neutrons, and 11 electrons?
24. a) An isotope has the same numbers of protons but different numbers of neutrons.
b) Examine the following isotope notation. Label the number on the top and bottom.
c) Examine the following isotope:
How many protons does this isotope contain? 90 How many neutrons does this isotope contain? 120
25. a) How do you determine the most common isotope of any element? Look on the periodic table for the average atomic mass
b) What is the most common isotope of sodium? Na - 23
c) What is the most common isotope of barium? Ba - 137
26. Find the average atomic mass of Element X if 51.83% of Element X occurring in nature has a mass of 106.905 amu and 48.17% of the atoms have mass of 108.905 amu.
average atomic mass = atomic mass x % abundance
100%
Step 1: Perform this calculation for EACH isotope; if there are 3 isotopes then do this equation 3 times!
Step 2: Add up all the atomic masses to calculate the average atomic mass – remember this is a WEIGHTED average (not the same as a normal average).
X1 .5183 x 106.905amu = 55.408861 amu
X2 .4817 x 108.905amu = +52.459538 amu
107.86839 amu
27. Write the full electron configuration for the following elements.
a) titanium 1s22s22p63s23p64s23d2
28. What element has the orbital diagram below? potassium How do you know? Count arrows = atomic number
29. What element has the orbital diagram below? argon How do you know? Count arrows = atomic number
30. Draw the Lewis/Electron Dot structure for the following elements:
a) Sodium b) Iodine c) Aluminum d) Oxygen
group 1A = 1 val. e- group 7A = 7 val. e- group 3A = 3 val. e- group 6A = 6 val. e-
so one 1 dot so 7 dots so 3 dots so 6 dots
e. Lewis/Electron dot structures show what type of electrons? Valence electrons in the valence (outermost) shell (s and p sublevels) *remember: group # = # valence electrons (for group A elements)
31. What is the name of the lowest, most stable energy level an electron occupies within an atom? ground state
32. What happens within an atom when an electron undergoes excitation?
excitation: lower to a higher energy level & absorb photons (energy)
de-excitation: higher to lower energy level & release (emit) a photon & visible light
33. How can the identity of an unknown be identified using the flame test? Explain. Color match – each element has its own unique color
Nuclear Chemistry34. a) ® + Is this alpha, beta, or gamma decay? beta
b) ® + Is this alpha, beta, or gamma decay? alpha
c) ® + Is this alpha, beta, or gamma decay? beta
35. Fill in the chart below.
Type of Decay / Particle Emittedalpha (a) / Helium nucleus (42He)
Beta Decay (b) / (fast moving electron)
gamma (g) / 00g (made of photons)
36. a) What is radioactive decay? Radioactive decay is the spontaneous emission of radioactive particles (or energy) from an unstable nucleus in an attempt to make a more stable nucleus.
b) What determines whether an atom is radioactive and unstable? Neutron-to-proton ratio (n0:p+ ratio)
37. What is half–life? The amount of time it takes for HALF of a radioactive isotope to decay.
38. Fusion involves atoms combining to make a larger atom whereas fission is when atoms split to make two or more smaller atoms that are more stable.
Periodic Table39. Mendeleev arranged the periodic table by increasing atomic mass whereas the modern periodic table is arranged by increasing atomic number.
40. Rows on the periodic table are called period and columns are called groups or families.
41. Fill in the following chart. The first one has been done for you as an example.
Group Name / Group Number / Number Valence ElectronsAlkali metals / 1A / 1 val. e-
alkaline Earth metals / 2A / 2 val. e-
boron group / 3A / 3 val. E
carbon group / 4A / 4 val. E
nitrogen group / 5A / 5 val. E
oxygen (chalcogen) group / 6A / 6 val. E
halogens / 7A / 7 val. E
noble (inert) gases / 8A / 8 val. E
42. Which group of metals is the most reactive group? alkali metals Why? They have 1 valence e- that can easily be lost to gain a full octet (because it’s easier to lose 1 than gain 7 e-).
43. Which group of nonmetals is the most reactive group? halogens Why? They have 7 valence e- so they can easily gain 1 electron to get a full octet (because it’s easier to gain 1 than to lose 7 valence electrons).
44. Which group of elements is the least reactive? noble gases Why? They have 8 valence electrons to complete a full octet; therefore, they don’t need to bond with other atoms to gain/lose/share electrons to acquire a full octet.
45. a) Fill in the chart below by placing a check mark by the properties that match each type of element.
Physical/Chemical Property / Metal / NonmetalLustrous (shiny) / Ö
Brittle (shatter) / Ö
Malleable (bendable) / Ö
Conductive / Ö
Dull / Ö
Reacts with Acid and CuCl2 / Ö
Gaseous / Ö
Solid / Ö
b) Unknown X is lustrous, malleable, and reactive with acid. This unknown is probably a(n) metal because it has all metallic properties.