CHM142 Elgin Community College Dr. Trail

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1 Final Exam total = 150 points Name Use only the space provided and show all your calculations. If you can t do the first part of a problem, then make up a number and use that for the rest of the problem. Best of luck! 14.7 psi = 1 atm = 760 mm Hg, Avogadro s number 6.02x10 23, R = L*atm*K -1 *mol -1, R = J*K -1 *mol -1 1) (4 pts) Name the following substances: NaHCO 3 H 2 SO 4 Ta 3 N 5 HClO 4 2) (4 pts) Write the chemical formulas for the following substances: sodium sulfate ammonia diphosphorus pentoxide iron (II) carbonate 3) (4 pts) The number of protons in the nucleus of a specific atom is equal to its a. atomic weight b. mass number c. atomic number d. mass number minus the atomic number 4) (4 pts) The most stable ion of chlorine is isoelectronic with the a. magnesium ion b. fluorine ion c. argon atom d. sodium ion 5) (4 pts) The energy of a photon is greatest in the case of a. x-radiation b. ultraviolet radiation c. visible light d. infrared radiation 6) (4 pts) Which ion has twenty-four electrons? a. S 2- (c) Ni 2+ b. Fe 2+ (d) Cu 2+

2 7) (4 pts) List the sources of Energy in the United States from 1 being the most used to 7 being the least used don t worry, I won t be too picky about the order ) Nuclear Power Wind power Natural Gas Coal Hydroelectric (water power from dams) Solar Petroleum 8) (2 pts) Most of Illinois s electricity is obtained from: 9) (6 pts) Please fill in the following Table Boiling point H 2 O Freezing Point H 2 O F C K Absolute Zero (coldest possible Temperature) 0 10) (4 pts) I have listed several temperatures below CIRCLE the temperatures that are reasonable CROSS OUT the bogus ones (one is right and one is wrong for each example) (the temperatures are approximate so if within a few degrees or so, it s o.k.) 180 C or 363 K Temperature to bake cookies -70 F or -70 C which is colder? 0 F or 0 K absolute zero 68 C or 19 C Room temperature 11) (4 pts) Predict which element would have the largest difference between its third and fourth ionization potentials. (a) Sodium (b) Silicon (c) Aluminum (d) Magnesium 12) (4 pts) In all +1 ions, there is a) one more proton than neutrons b) there is one more neutron than protons c) one more electron than and protons d) one more proton than electrons e) one more positron than electrons f) one more electron than positrons 13) (4 pts) Gallium, in gallium(i) nitride, has the following electronic configuration (a) 4s 2 3d 10 4p 1 (b) 4s 2 3d 10 (c) 4s 2 4d 10 4p 1 (d) 3d 10 (e) 5s 2 5p 3 (f) 4s 2 4d 10

3 14) (12 pts) Write Please convert the following and watch significant figures :, 454 g = 1 lb; 1.0 kg = 2.2 lb; 16 oz = 1 lb; 7.5 g = oz 1.25 km = cm 12 L*atm = J (hint use the two R s) 0.30nm x 0.20nm x 1.0nm = ml 15) (4 pts) In atomic absorption spectroscopy, (a) a photon is emitted causing an electron to fall from one atomic energy level to another (b) a photon is absorbed causing an electron to fall from one atomic energy level to another (c) a photon is emitted causing an electron to rise from one atomic energy level to another (d) a photon is absorbed causing an electron to rise from one atomic energy level to another (e) an electron is emitted causing a photon to rise from one atomic energy level to another 16) (4 pts) An atom has a valence shell electron configuration of ns 2 np 5. To which group of elements in the periodic table does it belong? (a) Transition metals (b) Rare earth metals (c) Chalcogens (d) Alkaline earth metals (e) Alkali metals (f) Halogens 17) (4 pts) What is the oxidation number of phosphorus in H 3 PO 3? (a) +1 (c) +3 (b) +2 (d) +4 18) (4 pts) The methane molecule, NH 3, has a structure best described by the term (a) pyramidal (b) trigonal pyramidal (c) orthorhombic (d) triangular (e) trigonal bipyramidal (f) rhombohedral

4 19) (4 pts) When dilute aqueous solutions of lead (II) nitrate and potassium bromide are mixed, a precipitate is observed. The products of this reaction are: (a) Pb 2+ (aq) + Br (aq) + KNO 3 (s) (b) Br 2 (aq) + NO 2 (g) + PbK 2 (s) (c) PbO(s) + K + (aq) + Br (aq) + NO 2 (g) (d) PbBr 2 (s) + K + (aq) + NO 3 (aq) 20) (4 pts) When the following system is balanced H 2 O + Cl ClO 2 + H + + e How many electrons are needed to balance the equation? 21) (4 pts) What do all parts of this symbol mean? What is T? 100 H atoms 22) (4 pts) Calculate the mass of: (WORK MUST BE SHOWN FOR CREDIT).. 23) (6 pts) Atomic Structure Rank the following masses (1 being the heaviest) electron proton neutron Draw a picture of a helium atom including all of it s parts Include charges.

5 24) (4 pts) Balance this reaction H 2 SnCl 6 + H 2 S SnS 2 + HCl 25) (4 pts) Calculate the pressure exerted by 54 g of steam (H 2 O) confined to a volume of 18 L at 100. C. 26) (4 pts) In the Periodic Table Outline below, please label. a) Lanthanides (Rare Earth Metals) b) Alkaline earth metals c) Actinides (Transuranic elements) d) Alkali metals e) Halogens f) Noble Gases g) Pnictides h) Chalcogenides i) Transition Metals 27) Consider the following ion: ICl 2 + # valence electrons: Draw the Lewis Dot Structure Predict the shape of the ion and draw it Do you expect it to be polar? What hybridization does each atom have? Discuss the bonding (sigma, pi, lone pairs)

6 28) Consider the following molecule: HArF # valence electrons: Draw the Lewis Dot Structure Predict the shape of the ion and draw it Do you expect it to be polar? What hybridization does each atom have? Draw all of the hybrid orbitals 29) (4 pts) What is the mass of one atom of carbon 12 ( 12 C) in grams? a) 12.0 g b) g (infinite sig. figs) c) 6.0 g d) 1.99 x g e) 1.06 x g 30) (6 pts) If 2 g of sugar is burned to heat 1.5 L of water, how much will the temperature rise if the starting temperature is 20. C? calories = m*c* ΔT Sugar contains 4 calories per gram. 31) (2.5 pts) Please determine the number of significant figures in each of the following numbers: NUMBER NUMBER OF SIGNIFICANT FIGURES *

7 32) (4 pts) A student measures the ph of distilled water by titrating with a burette and with an electronic ph meter. He/She obtains the following data: Burette: ph Meter (circle the best answer) The Burette (in the hands of a student): accurate precise accurate and precise The ph Meter is: accurate precise accurate and precise 33) (4 pts) In the reaction S 8 + 8O 2 (g) 8SO 2 (g) Assign oxidation states to each atom Which atom is being oxidized? Which atom is being reduced? 34) (4 pts) As a bicycle tire is inflated with 125 Joules of work, the surroundings absorb 180 Joules of heat. The change in the internal energy is: 35) (4 pts) The planet Mars has an atmosphere composed of 95.2% CO 2 2.7% N2 and 1.6% Ar. Assume the remaining gas is CO. The total pressure on mars is Torr. Calculate the pressures, in Torr of all four gases and the mole fraction % Torr Mole Fraction CO 2 N 2 Ar CO

8 36) (6 pts) If you have 200 g of CaCl 2, how many grams of a 20.% (m/m) solution can your prepare? How much water do you need to use (ml)? Show ALL of your work for credit 37) (6 pts) What is the molecule with this molecular orbital diagram? What is the bond order? Is it paramagnetic or diamagnetic? 38) (4 pts) Would you expect the bond distance to get shorter, longer or stay the same if you removed one electron? Answer and explain why. Part 1) E=h c= E=mc 2 Kinetic Energy = 1/2mv 2 (6 pts) Derive debroglie s relationship for the wavelength of matter =? remember to convert c to v

Answer Sheet for Sample Problems for Chemistry Level 1 Final Exam 2016 Study Guide

Answer Sheet for Sample Problems for Chemistry Level 1 Final Exam 2016 Study Guide Electrons in Atoms Chapter 5 1. What is the frequency of green light, which has a wavelength of 4.90 x 10-7 m? 8 c 3.00x10