CHEM Final Exam Name

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1 CHEM Final Exam Name Conversion factors: 1 mile = 1.61 km, 1 in. = 2.54 cm, 1 kg = lb, 1 lb = 454 g 1 L = qt., 1 qt. = 946 ml, J = 1 cal, 32 oz. = 1 qt., 4 qt. = 1 gallon, 2 pt. = 1 qt., 1 yard = m Constants: R h = 2.18 x J, h = 6.63 x J-s, c = 3.00 x 10 8 m/s, 1 J = 1N m = 1 m 2 kg/s 2, R = L-atm/mol-K or J/mol-K or m 3 -Pa/mol-K or L- torr/mol-k, 29.9 in. Hg = 1 atm, 760 torr = 1 atm, 760 mm Hg = 760 torr, kpa = 1 atm Equations: ΔE = q + w, KE = 1 2 mv2, E n = -R h n 2, E = R h, E = hν, c = λν, λ = h mv, w = f x d, P = mv, ΔE = ΔH PΔV, q = m s ΔT, q = C ΔT, Z eff = z s, PV = nrt, P total = P a + P b + P c..., n = Multiple Choice (5 pts. each) g m.w., P 1V 1 T 1 = P 2V 2 T 2 1. Which one of the following is chemical property of water? a) it boils at 100 C at a pressure of 1 atmosphere b) it freezes at 0 C c) it is clear and colorless d) it reacts rapidly with potassium metal to form potassium hydroxide 2. Which one of the following is an alkali earth metal? a) sodium b) magnesium c) silver d) lead 3. Which one of the following objects is the most dense? a) an object with a volume of 2.5 L and a mass of 12.5 kg b) an object with a volume of 139 ml and a mass of 93 g c) an object with a volume of m 3 and a mass of 4.22 x 10 4 mg d) an object with a volume of 3.91 x nm 3 and a mass of 7.93 x ng 4. Which one of the following numbers contains 6 significant figures? a) b) c) d) all of these

2 5. Which one of the following is not a diatomic element? a) oxygen b) nitrogen c) carbon d) hydrogen 6. How many electrons, protons, and neutrons are contained in an atom? a) 116 electrons, 116 protons, 92 neutrons b) 92 electrons, 92 protons, 116 neutrons c) 24 electrons, 42 protons, 92 neutrons d) 92 electrons, 92 protons, 24 neutrons 7. When a metal and a nonmetal react, the tends to lose electrons and the tends to gain electrons. a) metal, metal b) nonmetal, nonmetal c) metal, nonmetal d) nonmetal, metal e) none of these, these elements share electrons 8. Elements belonging to which group of the periodic table form ions with a 2+ charge? a) alkaline earth metals b) halogens c) chalcogens d) alkali metals 9. The formula of bromic acid is a) HBrO b) HBrO 2 c) HBrO 3 d) HBrO Which one of the following polyatomic ions has the same charge as the hydroxide ion? a) ammonium b) carbonate c) nitrate d) sulfate 11. Of the reactions below, which one is a decomposition reaction? a) NH 4 Cl NH 3 + HCl b) 2Mg + O 2 2MgO c) 2N 2 + 3H 2 2NH 3 d) Zn + Cu(NO 3 ) 2 Cu + Zn(NO 3 ) 2

3 12. Assume that element X has three naturally occurring isotopes. The mass and abundance of each isotope is: (19.61%), (53.91%), and (26.48%). What is the average atomic weight of element X? a) amu b) amu c) amu d) amu 13. Which one of the following is not an electrolyte? a) HCl b) Rb 2 SO 4 c) H 2 S d) KOH 14. What is the ΔE of a system that releases 12.4 J of heat and does 4.2 J of work on the surroundings? a) 16.6 J b) 12.4 J c) 4.2 J d) J 15. The reaction shown below is and therefore heat is by the reaction. 2Al (s) + 3O 2(g) 2Al 2 O 3(s) ΔH = kj a) endothermic, evolved b) endothermic, absorbed c) exothermic, evolved d) exothermic, absorbed 16. An object initially at 25 C absorbed 382 J of heat and experienced a temperature increase. Of the choices below for the final temperature of the object, which one would indicate the object with the greatest heat capacity? a) 45 C b) 36 C c) 79 C d) 91 C 17. Of the following regions of the electromagnetic spectrum, which one has the shortest wavelength? a) x-rays b) radio waves c) microwaves d) gamma rays

4 18. What is the frequency (in Hz) of electromagnetic radiation necessary to move an electron from n=2 to n=4 in a hydrogen atom? a) 4.1 x b) 6.2 x c) 5.4 x d) 8.2 x Which quantum number describes the orientation of an orbital in space? a) principle b) azmuthal c) magnetic d) spin 20. Which set of quantum numbers cannot be correct? a) n=6, l=0, ml=0 b) n=3, l=2, ml=3 c) n=3, l=2, ml=-2 d) n=1, l=0, ml=0 21. The compound most likely to be a gas at room temperature and pressure is a) C 2 H 6 b) Al 2 O 3 c) NaF d) SiO Which one of the following is the least reactive? a) Mg b) Sr c) Ca d) Ba 23. The oxidation number of manganese in potassium permanganate is: a) +1 b) +3 c) +5 d) The correct set of quantum numbers for the valence electron in potassium is: a) n=3, l=1, ml=0, m s = +½ b) n=3, l=1, ml=1, m s = +½ c) n=4, l=3, ml=0, m s = +½ d) n=4, l=0, ml=0, m s = +½

5 25. A gas originally at 25 C and 1.00 atm pressure in a 2.5 liter container is allowed to expand until the pressure is 0.85 atm and the temperature is 15 C. What is the new volume of the gas? a) 3.0 L b) 2.8 L c) 2.6 L d) 2.1 L

6 Complete the following problems showing all work. Use complete sentences for essay questions. Remember to use proper units, significant figures, and rounding. 1. Make the following conversions using the appropriate number of significant figures: (15 pts.) a lbs. to milligrams b miles to centimeters c. 52 F to Kelvin 2. Draw Lewis structures, predict the geometry and give the orbital hybridization of the central atom for each of the following substances. (20 pts.) structure shape hybridization a. XeF 4 b. NO 2 c. Which molecule above would have a dipole moment greater than zero?

7 ml of M sodium carbonate was reacted with 150 ml of M nitric acid in a double displacement reaction. (20 pts.) a. Write the balanced un-ionized and net ionic equations for this reaction. b. Which is the limiting reagent in this reaction (Show proof for your answer)? c. If 1.20 L of carbon dioxide gas was collected at 89.6 kpa and 25.0 C, what was the percentage yield for this reaction?

8 4. For the OF + ion do the following: a. Draw the Lewis structure and calculate the formal charges on each of the atoms (5 pts.) b. Draw an orbital bonding representation of OF +. (Show σ bonds as single lines and π bonds as orbitals) (7 pts.) c. Draw a molecular orbital energy diagram for OF +. (using the normal orbital sequence for oxygen) Determine the bond order for this molecule and describe its magnetic properties. (8 pts.)

9 Bonus: Draw three resonance forms for HCNO and determine which contribute most to the overall bonding description of this compound. Justify your answer. (10 pts.)

Chemistry 104 Final Exam Content Evaluation and Preparation for General Chemistry I Material

Chemistry 104 Final Exam Content Evaluation and Preparation for General Chemistry I Material What is 25 mph in mm s 1? Unit conversions What is 1025 K in o F? Which is larger 1 ft 3 or 0.1 m 3? What is