GENERAL CHEMISTRY I FINAL
December 17, 2001
INSTRUCTIONS:
PRINT YOUR NAME ————> NAME .
WORK ALL PROBLEMS
SHOW YOUR WORK FOR PARTIAL CREDIT
USE THE CORRECT NUMBER OF SIGNIFICANT FIGURES
THE LAST TWO PAGES ARE A PERIODIC TABLE AND A SCRATCH SHEET
1 .
2 .
h = 6.626 X 10-34 J-s 3 .
c = 2.9979 X 108 m/s 4 .
J = (kg•m2)/s2 5 .
6 . 7 .
8 . 9 .
10 .
11 . 12 .
TOTAL(150) .
1. There is rule of thumb that says that a pint (pt) of water weighs a pound (lb). If 1.00 pint of water has a mass 1.00 pound, what would the density of water be in g /cm3? (1 kg = 2.20 lb,
1 pt = 16.0 oz, 1 oz = 29.6 cm3.)
2. Provide a short answer or explanation to the following questions.
(a) What is the formula of the ionic compound formed from the group IIA element from the third period of the periodic table and the halogen in the second period?
(b) The symbol for an atom is 65Cu. How many of the following particles does this atom have?
Protons ______Neutrons______Electrons______
(c) Identify the following elements as a metal or nonmetal.
Sodium______neon ______aluminum ______sulfur ______
(d) Why is an atom of K bigger than an atom of Na? (Note the answer is not that K is below Na in the periodic table.)
(e) What is the percent by mass of calcium in CaCl2, molar mass = 110.99 g/mol?
3. Erythrose, C4H8O4, is a sugar that can be derived from glucose
(a) What is the empirical formula of erythrose?
(b)What is the molar mass of erythrose?
(c) What is the number of moles in 34.9 g of erythrose?
(d) How many individual molecules of erythrose are there in 0.125 moles?
4. How many g of carbon dioxide can be prepared from explosion of 12.54 g of nitroglycerin (C3H5N3O9, molar mass = 227.09 g/mol)?
4C3H5N3O9 6N2 + 12CO2 + 10H2O + O2
5. When Na2S reacts with ZnCl2 a white precipitate of ZnS forms.
(a) Write the balanced equation for this process.
(b) Write the total ionic equation for this process. Do not forget to include charges on ions and subscripts such as (s), (l), (g), or (aq) to identify the state of the substance.
(c) Write the net ionic equation for this process. Do not forget to include charges on ions and subscripts such as (s), (l), (g), or (aq) to identify the state of the substance.
(d) What are the spectator ions?
6. If 307.6 J of heat is absorbed by a 35.7 g piece of aluminum at 25.8 C, what is the final temperature of the aluminum? (The specific heat of aluminum is 0.900 J/(gC))
7. What are the electron configurations of the following molecules or ions.
(a) Na
(b) Cl
(c) Mn
(d) O2-
(e) Ca2+
8. Arrange the three species in increasing order for the property given in the left column.
(a) 1st ionization energyNPAs ______< ______< ______
(b) atomic radiiNPAs ______< ______< ______
(c) radiiMg Ca2+ Mg2+ ______< ______< ______
(d) ionization energy Mg Mg+ Mg2+ ______< ______< ______
(e) electronegativitySiGeC ______< ______< ______
(f) electronegativitySiSCl ______< ______< ______
(g) radiiSS2-Se ______< ______< ______
(h) electronegativityNaKLi ______< ______< ______
9. Draw a valid Lewis structure for the following molecules or ions. Assign formal charges to each atom in (e). For each structure, the first atom in the formula is the central atom.
(a) NH3 (b) SO32- (c) PF6-
(d) ClF4-(e) NFO2-
10. Answer the following questions about the molecule, SCl2 .
(a) What is the Lewis structure?(b) What is the molecular shape?
(c) Is the molecule polar? (d) Explaion your answer in (d)
(e) What is the hybridization of Sulfur?
11. How many mL of 0.234 M SO2 solution is needed to completely react 24.7 mL of 0.123 M KMnO4 solution.?
5SO2 + 2KMnO4 + 2H2O K2SO4 + 2MnSO4 + 2H2SO4
12. Calculate the enthalpy of the following reaction:
2B5H9 + 12O2 5B2O3 + 9H2O
(standard Hf values : B5H9 = +73.2 kJ, B2O3 = -1263.6 kJ, H2O = -285.8 kJ)