Chem 177 Exam I February 8, Teaching Assistants and Recitation Sections. Page Points Score Name Sections Time Stacey Althaus 5 10:00 2

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1 Dr. Joe Burnett Spring 010 This exam consists of questions on 7 pages Chem 177 Exam I February 8, 010 Answer Key Name Recitation TA Recitation Section Grading Teaching Assistants and Recitation Sections Page Points Score Name Sections Time Stacey Althaus 5 10: pts 18 pts 16 pts Kyle Marchuk Kristopher McKee Justin Smith Anthony Stender 1, 10 11, 1 8, 3 8:00, 1:10 :10, 1:10 1:10 8:00, 9: pts 6 pts Nishad Thamban Chandrika Songchen Xu 4, 6 7, 9 9:00, 11:00 11:00, 1:10 TOTAL 10 pts Questions are written on both sides of each page. There is a periodic table and an equation on the last page. You may remove this page for scratch paper. Show all work. Answers should include appropriate units and contain the correct number of significant figures. The last day to drop Chem 177 and add Chem 50 is Thursday, March 4, at 4:00 PM. See your advisor to obtain the drop/add form and go to the General Chemistry Office, room 1608 Gilman Hall.

2 1. ( pts) What subatomic particle or particles are found outside of the nucleus of an atom? electrons. (4 pts) The correct answer (reported to the proper number of significant figures) to the following is _. ( ) ( ) = a) b) 64.9 c) d) e) (8 pts) How many oxygen atoms are in 5.00 g of CO? For full credit, show all work, use units, and report your answer to the correct number of significant figures. 1 mol of CO : 1.0 g g = 44.0 g ( ) ( ) = = g CO 1 mol CO 44.0 g CO molecules 1 mol CO O atoms 1 CO molecule = O atoms 3 sig figs or 5.00 g CO 1 mol CO 44.0 g mol O 1 mol CO O atoms 1 mol O = O atoms or % O = 16.0 amu 1.0 amu amu 100 = 7.7 3% O in CO g CO = g O g O 1 mol O 16.0 g O O atoms 1 mol O = O atoms 4. (10 pts) Fill in the gaps in the following table. symbol Au 4 Cr 6+ protons 79 4 neutrons = 8 electrons mass number net charge 0 or neutral +6

3 3 5. (4 pts) Report the result of each calculation to the correct number of significant figures. (All numbers in the following are measured values and are NOT exact numbers.) 15.0 A = B. = (6 pts) The mass of 7 glucose molecules is amu. What is the mass of glucose molecules in grams? For full credit, show all work, include units and report your answer to the correct number of significant figures. (Glucose is a simple sugar.) 1 amu = gram glucose molecules amu 7 glucose molecules gram 1 amu = g sig figs or calculate mass of 1 glucose molecule: amu 7 glucose molecules = amu glucose molecules amu 1 glucose molecule gram 1 amu = g 7. ( pts) Which is more dense, a 0.0 lb block of concrete or 1.0 g piece of gold? Density of concrete = 000 kg/m 3 ; density of Gold = kg/m 3 ) the gold (density is an intensive property, amount is immaterial) 8. ( pts) Which of the following is a chemical property? a) melting point b) mass c) flammability d) volume e) temperature 9. (4 pts) Boron has two isotopes, boron 10 and boron 11. Which isotope is more abundant in nature? a) boron 10 b) boron 11 c) the two isotopes are present in equal abundances d) not enough information has been provided to answer this question

4 10. (4 pts) What mass of lead has the same volume as.0 g of gold? For full credit, you must show all work and include units. a) 0.0645 g b) 11.93 g c) 15.5 g d) 31.

4 4 10. (4 pts) What mass of lead has the same volume as.0 g of gold? For full credit, you must show all work and include units. a) g b) g c) 15.5 g d) 31. g d = m V e) none of the above 11. (4 pts) Read the volume of liquid in the graduated cylinder to the correct number of significant figures. The units are in milliliters. Read the level at the bottom of the meniscus indicated by the arrow ml ( ml acceptable) 3 sig figs substance density at 5 o C lead (Pb) 13.6 g/cm 3 gold (Au) 19.3 g/cm 3 V gold = m gold.0 g d = gold 19.3 g/ml = 1.14 ml gold -> 1.14 ml lead m lead = d lead V lead = 13.6 g/ml 1.14 ml = 15.5 g 1. ( pts) Give one example of an intensive property. density, melting point, boiling point, color, hardness, conductivity, % composition, etc. 13. ( pts) Give one example of an extensive property. mass, volume, length, width, etc. 14. (4 pts) What was the major contribution to our understanding of atomic structure that was determined in the Millikan oil drop experiment? Please be brief. the determination of the charge on a single electron.

5 5 15. (6 pts) What is the percent composition by mass of oxygen in CO? For full credit, show all work, use units, and report your answer to the correct number of significant figures. % O = 16.0 amu 1.0 amu amu 100 = 7.7 3% O in CO 3 sig figs 16. (6 pts) What is the mass in grams of.18 moles of CO? For full credit, show all work, use units, and report your answer to the correct number of significant figures. 1 mol of CO : 1.0 g g = 44.0 g.18 mol CO 44.0 g 1 mol CO = 95.9 g 3 sig figs 17. (4 pts) What is the mass of 1 mole of Fe(OH)? 55.8 g + (16.0 g g) = 89.8 g a) 89.9 amu b) 89.9 g c) 73.8 amu d) 73.8 g e) none of them 18. ( pts) Iron forms cations with a +3 charge Fe 3+ and a + charge Fe +. Which of the following is the correct name for Fe(OH)? a) ferric hydroxide b) ferrous hydroxide c) iron (IV) hydroxide d) iron hydroxide e) iron (II) hydrogen oxide

6 19. (6 pts) Fill in the blanks in the following table of acids. 6 Acid Name hydrosulfuric Acid Formula H S nitric HNO 3 perchloric HClO 4 0. (14 pts) Fill in the blanks in the following table. Compound Name Compound Formula ionic or molecular ammonium sulfate (NH 4 ) SO 4 ionic tetraphosphorus decasulfide P 4 S 10 molecular nickel (III) oxide Ni O 3 ionic dinitrogen tetroxide N O 4 molecular 1. (4 pts) The incomplete combustion of hydrocarbons yields poisonous carbon monoxide according to the following reaction. Balance the equation. C H 6 (g) + 5 O (g) 4 CO(g) + 6 H O(l). ( pts) What is the name for C H 6? ethane

7 7 Chem 177 Periodic Table Exam I C = 5 9 ( F 3) F = ( C) + 3 density of water at 5 o C: 1.00 g/ml

Chem 177 Exam I February 8, Teaching Assistants and Recitation Sections. Page Points Score Name Sections Time Stacey Althaus 5 10:00 2

Chem 177 Exam I February 8, Teaching Assistants and Recitation Sections. Page Points Score Name Sections Time Stacey Althaus 5 10:00 2 Dr. Joe Burnett Spring 2010 This exam consists of 22 questions on 7 pages Chem 177 Exam I February 8, 2010 Name Recitation TA Recitation Section Grading Teaching Assistants and Recitation Sections Page