chemistry 121: atomic and molecular chemistry midterm 2 november … · chemistry 121: atomic and...

Chemistry 121: Atomic and Molecular Chemistry Midterm 2 November 9, 2012

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Name: ______________________ Student Number _______________ 1) If 5.0 grams of Octane (C8H18) is combusted with 5.0 grams of Oxygen (O2) in a closed container to produce Water and Carbon Dioxide, determine the limiting reagent and the number of grams of each compound that will be in the container when the reaction is complete. Be sure to show the complete balanced equation. 1 Mark for balanced equation 1 Mark for indicating O2 is limiting 1 mark for correct final mass of Octane (3.6 grams) 1 mark for correct final mass of H2O (2.0 grams) 1 mark for correct final mass of CO2 (4.4 grams)

/50 Total Marks

/5


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2) Calculate the wavelength of a photon with enough energy to remove an electron from a 3d orbital of a hydrogen atom.

3) Indicate the orbital hybridization of the atom the arrow points to and the bond angle where the central angle is the indicated atom.

/4

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SP2 – angle 240 degrees (if 120 degrees -1/2)

SP2 – angle 120 degrees


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4) Fill in the following table. Use the back of adjacent page for rough work. (16 points) 1 mark each

Formula Best Lewis Structure Central Atom hybridization

Molecular Shape name Polar? Y/N

ClO3-

sp3 Trigonal pyramidal Y

SCl4 sp3d See Saw Y

CS2 SP Linear N

IF3

sp3d T-Shaped Y


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5) What is the percent calcium in CaCO3? 40.1 g/mol Ca 100 g/mol molecule = 0.401 = 40% Ca Mass Percent Mole percent 20% 6) How many grams of Calcium Carbonate would you need to have 0.5 grams of Calcium?

7) If you dissolved the number of grams of Calcium Carbonate indicated in question 6 into 100 mL of 1% Nitric acid, what would the concentration of the Calcium be in mg/L and Molarity?

8) Indicate the charge on Calcium in question 7 and provide it’s condensed electron configuration?

Ca+2 [Ar]

/2

/4

/2

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Multiple Choice (circle best answer) 9) According to molecular theory, which of the following diatomic species are would be attracted by a magnetic field? (A) C2 (B) N2 (C) O2 (D) F2

10) Which of the following has the largest Bond Order? (A) H2 (B) N2 (C) O2 (D) F2

11) A molecule that has a classification of AX3E2, would have the following shape? (A) Trigonal Planar (B) Trigonal Pyridmal (C) T-Shaped (D) Bent

12) A molecule that has a classification of AX3E would have the following shape? (A) Trigonal planar (B) trigonal pyridmal (C) T-Shaped (D) Bent 13) Which of the following would have the most polar bond? (A) CCl4 (B) CH4 (C) CHCl3 (D) CF4 (E) CO2 14) Which of the following would be considered a polar molecule? (A) CCl4 (B) CH4 (C) CHCl3 (D) CF4 (E) CO2 15) Which of the following has the longest C-C bond? (A) C2H2 (B) C2H4 (C) C2H6 (D) C6H6 (benzene) (E) They are all the same 16) Which of the following would you expect to be the most reactive?

(A) Li (B) Na (C) Ca (D) Rb (E) K

17 Atoms which are sp hybridized tend to form ____ pi bond(s). (A) 0 (B)1 (C)2 (D) 3 (E) 4 18) Which of the following molecules contains a carbon atom that is sp2 hybridized? (A) C2H4 (B) CO2 (C) H3COH (D) C2H6 (E) none of the above

/10 (1 point each)


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h = 6.63 x 10-34 J s RH = 2.18 x 10-18 J c = 3.00 x 108 m/s

Select Electronegativities

chemistry 121: atomic and molecular chemistry midterm 2 november … · chemistry 121: atomic and...

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