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Unformatted text preview: CH101 (Bontems, Fall 2009 TTH) MONTGOMERY COLLEGE Exam 1 Name: ____KEY___________________ Multiple Choice – In the blank, write the letter of the best answer. (3pts each) 1. B 2. C 3. B How many significant figures are in the measurement 2.000 x 104 mg? a. 5 c. 1 b. 4 d. none of these How many significant figures are in the measurement 0.06060 g? a. 2 c. 4 b. 3 d. 5 The correct answer to report following sig fig rules is: 5.0 g = 50.00 g/mol a. 0.1 mol c. 0.100 mol b. 0.10 mol d. 0.1000 mol e. none of the above 4. D The correct answer to report following significant figure rules is: 43.7 – 2.341 = a. 41.359 g c. 41.3 g b. 41.36 g d. 41.4 g e. none of these 5.D A modest‐sized house has an area of 195 m2. What is it’s area in dm2? a. 1.95 dm2 c. 1950 dm2 b. 19.5 dm2 d. none of the above (19500 dm2) 6. C The average temperature of the universe is about 3 K. Convert his to °C. a. 270. °C c. ‐270. °C b. 276 °C d. ‐272 °C If element X consists of two isotopes 60X (75%) and 64X (25%), the atomic mass would be 7.B approximately: a. 60 amu c. 64 amu b. 61 amu d. 124 amu 8.D Which of the following pairs do you expect to be most similar? a. N and Ni c. Si and P b. Na and Mg d. Cl and F 9.C An cation is formed when an atom: a. gains neutrons b. gains protons c. loses electrons d. gains electrons e. more than one of the above 2 10.D What is the molar mass of Mg(NO3)2? a. 204.3 g/mol c. 86.3 g/mol b. 134.3 g/mol d. 148.3 g/mol 11. D____ Calculate the percent oxygen in Ca(NO3)2. (58.5%) a. 53.9% c. 64.7% b. 10.8% d. none of these 12. Label each statement as (T) or false (F). (2 pts each) _F___ PCl3 is an ionic compound. _T___ Bromine is a halogen. _F___ Sodium is an alkaline earth metal. _T___ The element Ag forms a +1 charge. _F___ Calcium is a transition metal. _T___ One mole of Fe2(SO4)3 contains 3 moles sulfur and 12 moles oxygen. 13. Complete the following table. (6 pts) Symbol Charge Mass Number Neutrons Protons Electrons P‐3 ‐3 35 20 15 18 Ni+2 +2 58 30 28 26 14. Explain or list the principles of Dalton’s atomic theory. Use complete sentences. (3 pts) All elements are composed of atoms. Atoms of an element have the same mass and properties. Atoms combine in whole # ratios. Atoms cannot change into other atoms by chemical rxns. Explain the difference between a mixture and a compound. Use complete sentences. (2 pts) Mixtures are 2 or more substances mixed only (not bonded) and can have any ratio of the substances. Cmpds are atoms bonded together in fixed ratios. What do each of the letters in amu represent? When would you use amu? (2 pts) Amu = atomic mass unit Use this unit for the mass of p, n, e‐, one atom or one molecule. 3 15. Calculate the empirical formula and molecular formula for a compound which was found to have 66.6% C and 7.01% H, 26.4% F and a molar mass of 144.1 g/mol. (Use 3 sig figs throughout.) (6 pts) Ans: empirical = C4H5F and molecular = C8H10F2 (Don’t forget to calculate the molecular formula.) 16. Name the following compounds: (1.5 pts each) CuNO2 __Copper (I) nitrate___________________________ H2SO3 ____sulfurous acid___________________________ N2O4 ___dinitrogen tetroxide______________________________ Pb(C2H3O2)2 __lead (II) acetate_________________________ K3N ___potassium nitride_______________________________ HF __hydrofluoric acid__________________________ 17. Write the correct chemical formula for the following: (1.5 pts each) aluminum hydroxide __Al(OH)3_________________ potassium sulfate ___K2SO4________________ mercury (II) permanganate _Hg(MnO4)2___________________ sulfur hexafluoride __SF6_________________ silver hydrogen carbonate ___AgHCO3________________________ nitric acid ___HNO3________________________ 4 18. A sugar crystal contains approximately 1.8 x 1017 sucrose (C12H22O11) molecules. What is its mass in mg? (5 pts) Dimensional Analysis Required. 0.10 mg 19. The iodide ion is a dietary mineral essential to good nutrition. The recommended daily allowance (RDA) for iodine is 150 µg/day. How much calcium iodide would you have to eat each week to obtain the recommended daily allowance? (6 pts) Dimensional Analysis Required. 1.2 x 10‐3 g CaI2 20. Turn the following into balanced equations: (3 pts each) a. 2Fe(OH)3 + 3H2SO4 → Fe2(SO4)3 + 6H2O b. Na3PO4 + Al(NO3)3 → AlPO4 + 3NaNO3 c. Combustion of anisole (C7H8O) 2C7H8O2 + 17O2 → 14CO2 + 8 H2O ...
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This note was uploaded on 11/10/2011 for the course CH 101 taught by Professor Susanbontems during the Fall '11 term at Montgomery College.
- Fall '11