Chemistry credit recovery or improvement is only offered if the student has failed the lab science course in the past. Please see your ACE instructor for this option. If you are taking the APEX course work, you will need to use the following:
If you are taking the alternative course work, please complete the following and test with your ACE teacher:
Students must complete the following to receive full credit:
Define Terms with examples for each term.
Summary of each video (minimum 3-5 sentences per video). Label clearly for teacher to see work. Important Questions after watching the videos and taking notes. Exam at: https://testmoz.com/class/16400 be sure to print (control + "P") results of submitted exam and staple to the front of each credit. Unit 6: Solutions and You
Review the videos and media and take notes on terms to know. If the terms are not on the media, please Google them in order to get the materials needed to take the test.
Terms to Know:Notes:Important Questions:(a) they can form more stable bonds due to greater orbital overlap.
(b) hybrid orbitals are spatially further apart from each other, reducing repulsive interactions between electrons. (
c) antibonding interactions are eliminated when hybrid orbitals form bonds.
(d) all of the above
(e) (a) and (b) only
3. The rate of a reaction is dependent upon:
(a) Keq
(b) D G°
(c) D G¹
(d) all the above
(e) none of the above
4. The barrier to a chair-chair interconversion of cyclohexane is 45 KJ/mol. What conformation of cyclohexane corresponds to this barrier?
(a) chair
(b) boat
(c) twist-boat
(d) half chair
(e) envelope
5. The rotational barrier about the C1-C2 bond of 1-chloropropane is 18 KJ/mol. From this we can reason that:
(a) a -CH3/-Cl eclipsing interaction is worth 18 KJ/mol
(b) a -CH3/-Cl eclipsing interaction is worth 10 KJ/mol
(c) a -H/-Cl eclipsing interaction is worth 6 KJ/mol
(d) all of the above
(e) none of the above
6. The pKa of acetic acid is 4.75. The D G° for the dissociation of acetic acid at 300 °K is:
(a) 3.90 KJ/mol
(b) 27.3 KJ/mol
(c) -27.3 KJ/mol
(d) -11.8 KJ/mol
(e) 11.8 KJ/mol
7. Which of the following is not a Lewis acid?
(a) H+
(b) AlCl3
(c) (H3C)3N
(d) H3C+
(e) (a)-
(d) are all Lewis acids
*Hand in ALL work to teacher with test results on the front.
Work should be 5-10 pages when completed for full credit.
Unit 7: Kinetics and Doing us a Solid
Review the videos and media and take notes on terms to know. If the terms are not on the media, please Google them in order to get the materials needed to take the test.
Terms to Know:Notes:Important Questions:
1. For each of the following pairs of substances, specify the type of interparticle bonding in each, and indicate which one has the higher boiling point:
a) NH3 or PH3 b) C4H10 or C6H14 c) CO2 or H2O d) HCl or LiCl e) Na or NaCl
2. For each of the following types of solids, describe its structure and the nature of the forces holding it together, and give the formula of at least one example: (a) ionic; (b) covalent (molecular); (c) metallic; (d) network covalent
3. List the substance types in (3) in order of increasing melting point.
4. Which of the types of substances in (3) conduct electricity as solids? as liquids?
5. Of the following substances: NaCl, diamond, Fe, F2, C3H7OH, which one
a) has the lowest boiling point? b) is held together by ionic bonds?
6. Define boiling point, critical temperature, critical pressure, and triple point.
7. Explain how each of the following affects the vapor pressure of a liquid: (a) surface area; (b) temperature; (c) intermolecular attractive forces; and (d) volume of liquid.
8. What are the three types of intermolecular attractive forces and list them in order of increasing strength?
9. The normal (1 atm) melting and boiling points of O2 are -218°C and -183°C, respectively. Its triple point is at -219°C and 1.14 x 10-3 atm, and its critical point is at -119°C and 49.8 atm. (a) Sketch the phase diagram for O2, showing the 4 points given above and indicating the area in which each phase is stable. (b) Which is denser, O2(s) or O2(l)? Explain. (c) As it is heated, will solid O2 sublime or melt at a pressure of 1 atm?
10. The vapor pressure of solid iodine (I2) at 30°C is 0.466 mm Hg. How many milligrams of iodine will sublime into an evacuated 1.00-liter flask?
11. The following data were obtained for the reaction of methane with oxygen:
CH4(g) + 2 O2(g) ® CO2(g) + 2 H2O(l)
time(min)
[CH4] (mol/L)
[CO2] (mol/L)
0
0.050
0
10
0.030
0.020
20
0.020
?
30
0.015
?
a) How many moles of CO2 are produced for each mole of CH4 that is used up?
b) What concentration of CH4 is used up after 10 minutes?
c) What is the concentration of carbon dioxide produced after 20 minutes?
d) Write an equation for reaction rate in terms of D[CO2] over a time interval.
e) What is the reaction rate for the formation of carbon dioxide between 10 and 20 minutes?
f) What is the average reaction rate between 0 and 30 minutes?
g) Write an expression for reaction rate relating D[O2] to D[CO2].
h) At what rate is O2 used up between 10 and 20 minutes?
12. Nitric oxide (NO) reacts with oxygen to form nitrogen dioxide:
2 NO(g) + O2(g) ® 2 NO2(g)
a) How could you tell how many steps are in this reaction?
b) The following two step mechanism has been proposed for this reaction:
NO + O2 ® NO3 (fast)
NO3 + NO ® 2 NO2 (slow)
Which step is the rate determining step?
c) Write a rate equation for the rate determining step of this reaction, assuming it occurs as a single step that depends only on the collision between reactants.
d) What happens to the rate in (c) if the concentration of NO3 is halved and the concentration of NO is tripled?
e) What is the order of the rate determining step with respect to NO? What is the overall order of this step?
13. Draw an energy diagram for a reaction where DH = -40 kJ, the activation energy of the uncatalyzed reaction is +120 kJ, and the activation energy for a catalyzed reaction is + 80 kJ. Indicate the position of the activated complex for both catalyzed and uncatalyzed reactions.
14. List three factors that affect reaction rate and briefly explain the basis for their effects.
15. The breakdown of nitrous oxide gas (N2O) to nitrogen gas and oxygen gas is believed to occur in two steps. In the first step, nitrous oxide breaks down to form nitrogen gas and a free oxygen atom.
a) Write a balanced equation for the overall reaction (do not use fractional coefficients).
b) Write balanced equations for each of the two steps.
c) Which substance could be considered a "reaction intermediate?"
16. The rate of the reaction, HgCl2(aq) + ½ C2O42-(aq) ® Cl-(aq) + CO2(g) + ½ Hg2Cl2(s), is followed by measuring the number of moles of Hg2Cl2 that precipitate per liter per second. The following data are obtained:
[HgCl2]
[C2O42-]
Initial Rate (mol/L·s)
0.10
0.10
1.3 x 10-7
0.10
0.20
5.2 x 10-7
0.20
0.20
1.0 x 10-6
0.20
0.10
2.6 x 10-7
a) What is the order of the reaction with respect to HgCl2, with respect to C2O42-, and overall?
b) Write the rate equation for the reaction.
c) Calculate k for the reaction.
d) When the concentrations of both mercury(II) chloride and oxalate ion are 0.30 M, what is the rate of the reaction?
*Hand in ALL work to teacher with test results on the front.
Work should be 5-10 pages when completed for full credit.
Unit 8: Network and Atomic Chemistry
Review the videos and media and take notes on terms to know. If the terms are not on the media, please Google them in order to get the materials needed to take the test.
Terms to Know:Notes:Important Questions:
1. Draw an energy diagram for an exothermic reaction where DH = - 20 kJ.
2. Classify each of the following processes as endothermic or exothermic. In each case, indicate which has greater heat content (enthalpy), reactants or products.
a) combustion of natural gas
b) condensation of water vapor
c) splitting of carbon dioxide into carbon and oxygen
d) solidification of melted wax
e) formation of sodium chloride (NaCl) from it elements
f) evaporation of alcohol
3. Propane gas, C3H8, is a common fuel for camp stoves.
a) What is DHf° for propane? (Use DHf° Table.)
b) Write a balanced thermochemical equation for the formation of propane from its elements.
c) Is this reaction endothermic or exothermic?
d) How many moles of H2 are needed to produce 1090 kJ according to the equation in b)?
e) How much heat is produced during the formation of 30.1 g of propane?
f) Write a balanced chemical equation for the complete combustion of propane.
g) Find DH for the reaction in f) using DHf° Table and Hess’ Law.
4. For each of the reactions below, calculate DH and indicate whether the reaction is endothermic or exothermic. (Use DHf° Table as needed.)
a) 2 NO(g) + O2(g) ® 2 NO2(g)
b) 6 PbO(s) + O2(g) ® 2 Pb3O4(s)
5. A coffee cup calorimeter is used to calculate the heat change when NH4Cl is dissolved in water. Use the data table below to calculate the heat change when 1.00 mole of NH4Cl is dissolved in water. (Assume that the heat change for the solution is the same as that of water alone and that you can ignore the mass of solid in the water, so use only the mass of water and the specific heat of water, 4.18 J/g °C, in calculating the heat change.)
Mass of NH4Cl = 5.03 g
Mass of water in the coffee cup = 60.0 g
Initial temperature of the water = 24.78 °C
Final temperature of the water = 19.23 °C
Is this process endothermic or exothermic?
6. To change the temperature of a particular calorimeter and the water it contains by one degree Celsius requires 6485 Joules. The complete combustion of 1.40 g of ethylene gas, C2H4, in the calorimeter causes a temperature rise of 10.7 degrees. Find the heat of combustion per mole of ethylene.
7. Calculate DH for the reaction: N2H4(l) + O2(g) ® N2(g) + 2 H2O(l)
given the following data:
2 NH3(g) + 3 N2O(g) ® 4 N2(g) + 3 H2O(l) DH = -1010 kJ
N2O(g) + 3 H2(g) ® N2H4(l) + H2O(l) DH = -317 kJ
2 NH3(g) + ½ O2(g) ® N2H4(l) + H2O(l) DH = -143 kJ
H2(g) + ½ O2(g) ® H2O(l) DH = -286 kJ
*Hand in ALL work to teacher with test results on the front.
Work should be 5-10 pages when completed for full credit.
Unit 9: Going Nuclear with Chemistry
Review the videos and media and take notes on terms to know. If the terms are not on the media, please Google them in order to get the materials needed to take the test.
Terms to Know:Notes:Important Questions:1. What is a nuclear equations and indicate the type of nuclear reaction.
2. The isotope undergoes beta emission with a half-life of 30 years.
a) Write a balanced nuclear equation for this reaction.
b) What fraction of Cs-137 remains in a sample of the isotope after 60 years?
c) What mass of Cs will be left in a 24.0 g sample of after 90 years?
d) What fraction of Cs-137 has decayed after 120 years?
3. What is the half-life of an isotope that is 75% decayed after 16 days?
4. Explain what makes an isotope radioactive. Why do radioactive isotopes undergo radioactive decay? How does the energy released by nuclear reactions compare to that released by ordinary chemical reactions? Why?
5. Write balanced nuclear equations for:
a) positron emission by Sr-83
b) the fusion of two C-12 nuclei to give another nucleus and a neutron.
c) the fission of U-235 to give Ba-140, another nucleus and an excess of two neutrons.
6. What new element is formed when K-40 decays by b-emission? Is the new element formed likely to be stable? Why or why not?
7. Why is nuclear fission considered a “chain reaction”? What is “critical” about critical mass? Why does nuclear fission produce radioactive waste?
*Hand in ALL work to teacher with test results on the front.
Work should be 5-10 pages when completed for full credit.
Unit 10: Global Carbon Cycle
Review the videos and media and take notes on terms to know. If the terms are not on the media, please Google them in order to get the materials needed to take the test.
Terms to Know:Notes:Important Questions:
1. Indicate the metric unit for: a) mass, b) length, and c) volume
2. The time is recorded from three different clocks as indicated below. The “true” time is exactly 8:30 A.M.
a) Which of the three clocks is the most precise? b) Which clock is the most accurate?
Measurement
Clock A
Clock B
Clock C
1
8:25.20 AM
8:29 AM
8:36 AM
2
8:25.00 AM
8:31 AM
8:36 AM
3
8:25.10 AM
8:30 AM
8:36 AM
c) Which clock(s) show a systematic error?
3. Indicate the number of significant figures in the following numbers:
a) 2,348 b) 7.0001 c) 0.0023
d) 24,500 e) 0.1060
4. Perform the following operations and express the answers in significant figures:
a) 1.24 x 8.2 = b) 6.78 - 3.3 =
c) 9.999 + 0.22 = d) (5.67 x 103) x (2.1 x 10-2)
5. Express the following numbers in scientific notation:
a) 650 (2 sig fig) b) 0.0005 (1 sig fig) c) 207,000 (3 sig fig)
6. Bozo determined the density of a sample of aluminum. For his sample, he found the volume was 0.350 cm3 and the mass was 0.822 g. Given that the density of aluminum is 2.70 g/cm3, calculate Bozo’s percent accuracy error.
NOTE: Use dimensional analysis (conversion factors) to answer the problems below. Answers must be in significant figures, include units and show work.
7. Find the mass in pounds (lbs) of a 275-gram sample of sugar.
8. Find the number of cm in 0.286 miles.
9. Find the volume in quarts of 10.7 kg of iron. The density of iron is 7.87 g/cm3.
10. Convert the density of ethanol (0.789 g/cm3) into units of pounds/liter.
11. Give two common examples of each of the following: a pure substance, a mixture, a solution, an element, a compound. Are your mixtures homogeneous or heterogenous?
12. List two chemical properties and two physical properties of the element magnesium.
13. Assuming each ant is 5.0 mm long, how many ants would it take to make a line, single file, from one end to the other of a 100-yard football field? (2 sig fig)
*Hand in ALL work to teacher with test results on the front.
Work should be 5-10 pages when completed for full credit.