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1 Name (PRINT CLEARLY) Seat Number Exam 1 (100 points) Chemistry September 20, 2017 On my honor, I have neither given nor received unauthorized aid on this exam. Signed Date Fill in the blanks with the appropriate word, phrase, number, or unit. 1. (3 points) The percent composition (by mass) of carbon in CO 2 is. 2. (4 points) If the compound Na 3 SbO 4 is correctly called "sodium antimonate", then what are the chemical formulas for the following compounds? antimonic acid sodium hydrogen antimonite 3. (6 points) Name the following compounds. P 4 S 10 Co(OCN) 2 CH 3 CH 3 4. (8 points) Write the formula for the following compounds. oxalic acid potassium phosphide ammonium dichromate cobalt (II) sulfate heptahydrate 5. (3 points) The properly BALANCED reaction for the complete combustion of C 4 H 10 is 6. (5 points) The number of oxygen atoms in a g sample of Mg 3 (PO 4 ) 2 (ar mass 262.8) is. The number of cations in this sample is 7. (4 points) List the formulas of the six strong acids:. 8. (2 points) The ecular formula of a compound with the empirical formula C 2 H 5 N and a ecular mass of g/e is.

2 page 2 9. (15 points) For the following three reactions, consider if the reactions will occur. If so, write the balanced MOLECULAR EQUATION and the NET IONIC EQUATION only. NOTE: You do NOT need to show the full ionic equation. HOWEVER, be sure to show the STATES for every substance (a) NH 4 NO 3 (aq) + Na 2 CrO 4 (aq) (b) CrCl 3 (aq) + K 3 PO 4 (aq) (c) HF (aq) + Ba(OH) 2 (aq)

3 page (10 points) SHOW ALL WORK. (Pay attention to significant figures here!) Naturally occurring copper is composed of two isotopes, 63 Cu and 65 Cu. The mass of 63 Cu is amu and its percent abundance is %. The average atomic mass of Cu listed in the periodic table is Determine the mass of 65 Cu in amu. 11. (10 points) SHOW ALL WORK. Lithium (Li) atoms are the smallest atoms among the alkali metals. Imagine that Li atoms are laid side by side in a single straight line of atoms along the diagonal (13.9 inch) of this page. Calculate the mass of Li (in picograms) in this "atomic-line" of Li atoms. (Assume the Li atoms are spherical.) (nanometers)] [density of Li = g/cm 3, atomic radius of Li = nm

4 page Iron (III) oxide is converted to iron metal when treated with carbon monoxide as shown in the following reaction. Consider the reaction of 5.00 g of Fe 2 O 3 with 5.00 g of CO which produces 2.63 g of metallic iron. a. (12 points) Fill in EVERY unshaded box in the table below. 3 CO + Fe 2 O 3 (s) 2 Fe (s) + 3 CO 2 (g) Initial a b Change c Final b. (10 points) CLEARLY show your work for each box above in the correct box below. If you have a limiting or excess reagent, be sure to indicate why you made your selection. For your convenience, some ar masses are written in small font below reactants and products. No work; No units; No points! box a box b box c other important calculations c. (4 points) How many grams of Fe metal should be formed in this reaction? Clearly show all work. d. (4 points) What is the percent yield of this reaction? Clearly show all work.

5 Name (PRINT CLEARLY) Seat Number Exam 1 (100 points) Chemistry September 20, 2017 On my honor, I have neither given nor received unauthorized aid on this exam. Signed Date Fill in the blanks with the appropriate word, phrase, number, or unit. 1. (3 points) The percent composition (by mass) of carbon in CO 2 is. 2. (4 points) If the compound Na 3 SbO 4 is correctly called "sodium antimonate", then what are the chemical formulas for the following compounds? antimonic acid sodium hydrogen antimonite 3. (6 points) Name the following compounds. P 4 S 10 Co(OCN) 2 CH 3 CH 3 4. (8 points) Write the formula for the following compounds. oxalic acid potassium phosphide ammonium dichromate cobalt (II) sulfate heptahydrate 5. (3 points) The properly BALANCED reaction for the complete combustion of C 4 H 10 is 6. (5 points) The number of oxygen atoms in a g sample of Mg 3 (PO 4 ) 2 (ar mass 262.8) is. The number of cations in this sample is 7. (4 points) List the formulas of the six strong acids:. 8. (2 points) The ecular formula of a compound with the empirical formula C 2 H 5 N and a ecular mass of g/e is. 9. (3 points) Consider the following species: 40 Ca Co 60 Ni Sn Fe i. Which has(have) an equal number of protons and neutrons? ii. Which has(have) 26 electrons

6 page (14 points) For the following three reactions, consider if the reactions will occur. If so, write the balanced MOLECULAR EQUATION and the NET IONIC EQUATION only. NOTE: You do NOT need to show the full ionic equation. HOWEVER, be sure to show the STATES for every substance (a) NH 4 NO 3 (aq) + Na 2 CrO 4 (aq) (b) CrCl 3 (aq) + K 3 PO 4 (aq) (c) HF (aq) + Ba(OH) 2 (aq)

7 page (10 points) SHOW ALL WORK. (Pay attention to significant figures here!) Naturally occurring copper is composed of two isotopes, 63 Cu and 65 Cu. The mass of 63 Cu is amu and its percent abundance is %. The average atomic mass of Cu listed in the periodic table is Determine the mass of 65 Cu in amu. 12. (10 points) SHOW ALL WORK. Lithium (Li) atoms are the smallest atoms among the alkali metals. Imagine that Li atoms are laid side by side in a single straight line of atoms along the diagonal (13.9 inch) of this page. Calculate the mass of Li (in picograms) in this "atomic-line" of Li atoms. (Assume the Li atoms are spherical.) (nanometers)] [density of Li = g/cm 3, atomic radius of Li = nm

8 page Iron (III) oxide is converted to iron metal when treated with carbon monoxide as shown in the following reaction. Consider the reaction of 5.00 g of Fe 2 O 3 with 5.00 g of CO which produces 2.63 g of metallic iron. a. (10 points) Fill in EVERY unshaded box in the table below. 3 CO + Fe 2 O 3 (s) 2 Fe (s) + 3 CO 2 (g) Initial a b Change c Final b. (10 points) CLEARLY show your work for each box above in the correct box below. If you have a limiting or excess reagent, be sure to indicate why you made your selection. For your convenience, some ar masses are written in small font below reactants and products. No work; No units; No points! box a box b box c other important calculations c. (4 points) How many grams of Fe metal should be formed in this reaction? Clearly show all work. d. (4 points) What is the percent yield of this reaction? Clearly show all work.

Chapter 3. Mass Relationships in Chemical Reactions

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