"Practice Final " General Review of the material for the final exam. Answers to this 20 question exercise will be in the Unit 8 Answer Book after Monday evening, 3/16 ---MD

1. How many moles are in 15.0 grams of potassium carbonate, K2CO3 (MW = 138.0 g/m)?

a) 6.53 b) 2.07 c) 0.151 d) 0.109 e) 0.920

2. Glucose is a molecule with six carbon atoms, twelve hydrogen atoms and six oxygen atoms. The molecular formula for glucose is

a) CH2O b) C6H12O6 c) C(H2O)6 d) (C3H6O3)6 e) C3H6O3

3. The quantum number, m(l), represents the

a) number of valence electrons

b) shape of the orbital

c) number of orbitals

d) orientation of the orbital

e) momentum of the electron

4. The number of orbitals in the "4 p" subshell is

a) one b) three c) five d) seven e) sixteen

5. Which set of quantum numbers is not allowed?

a) n = 2, l = 1, m(l )= +1

b) n = 3, l = 1, m(l )= +1

c) n = 3, l = 0, m(l )= 0

d) n = 4, l = 3, m(l)= +1

e) n = 4, l = 4, m(l) = +2

6. a) Define " first ionization energy"

.

b) Rank the elements Na, Mg, K, and Cl in order of increasing first ionization energy,

Lowest ____ < _____ < _____ < ______ Largest energy

7. Given the ions, K+, Ca (2+), Cl (- )and S (2 -) which one , if any, has the smallest ionic radius?

a) K+ b) Ca (2+) c) Cl (- ) d) S (2-) e) all have the same ionic radius

Briefly explain your choice

8. Sketch the "shape" of a 2 p(x) atomic orbital. Label your axis. What is the probability of "finding" and electron along the "z" axis in this case?

9. a) Using the solubility table from the text, Fig 4.7, page 167, predict whether the following ionic compounds are likely to be soluble in water. If soluble, indicate the formulas for the ions formed in solution.

For example: NaCl soluble Na+ (aq) and Cl - (aq)

a) CaCl2

b) MgCO3

c) NH4NO3

b) If you mixed aqueous solutions of barium chloride and sodium nitrate together, do you expect a precipitate to form?

BaCl2 (aq) + NaNO3 (aq) ---> ?

10. Determine the oxidation number for the indicated element in each case,

a) C2O4 (2-) (oxalate ion) carbon ______

b) HNO3 nitrogen ______

c) SF6 sulfur ______

11. Given the reaction:

CO (g) + 2 H2 (g) ------> CH3OH (l)

a) If you mix 12.0 grams of H2 and 74.5 grams of CO together, which one is the limiting reactant?

b) Based on the limiting reactant, how many grams of methanol, CH3OH could be produced from the reaction mixture in part (a) ?

12 Briefly explain why is it unlikely anyone will isolate the ionic compound, KF2 , "potassium difluoride" ?

13. Formaldehyde has the formula, H2CO. Draw the appropriate Lewis structure for formaldehyde and predict its molecular geometry from VSEPR Theory and from Valence Bond Theory. Do the two different approaches to predicting molecular geometry of formaldehyde agree? What is the hybridization of the carbon atom in fromaldehyde? What is the HCO bond angle?

14.a)Which one of the following compounds is an exception to the octet rule?

a) SCl4 b) PCl4 (+) ion c) OF2 d) SiCl4

b) Draw the Lewis structure for OF2. Is this molecule linear or bent ? What is the F-O-F bond angle ?

15 . Using VSEPR,what is the molecular geometry for the phosphorus hexafloride ion, PF6 (- )?

16. Knowing that carbon has a total of four bonding pairs ( single, double or triple) in virtually all its compounds and that it can form "chains" or "rings" of carbon atoms, draw two possible Lewis structures for the compound, C3H4.

17. w PCl5 + x H2O ---> y POCl3 + z HCl

When the above equation is balanced, values for the coefficients w, x, y, z will be:

a) w=1, x=1, y=1, z=2 b) w= 1, x= 2, y= 2, z= 4

c) w= 2, x= 2, y= 2, z=2 d) w= 2, x= 2, y=2, z=4

18 The following series of questions are based on the compounds,

a) Which compound has the largest molar mass? ________

b) Which compound contains the lowest percent by mass carbon? ________

c) For which compound does 0.256 mols weigh 7.68 grams? ________

d) Is the formula C2 H4O an example of an empirical formula? Briefly explain.

19. The formula for the ionic compound formed between:

a) barium ion, Ba (2+ ) and nitrate ion, NO (3- )

b) ammonium ion, NH(4+) and carbonate ion, CO3 (2- )

20. Vitamin C, ascorbic acid, contains the elements, C, H and O. An analysis of a sample of vitamin C gives the percent composition by mass as 40.95 % C, 4.52 % H and 54.53 % O.

If the molar mass is 176 gm/mol, find the molecular formula for vitamin C.