YOUR NAME                                    (circle it if it is OK to leave your paper outside 640 Choppin)
 
Chemistry 1201 Lecture Section         2 or        3

HOMEWORK #2 due on Thursday, March 7 (sec. 2) and Friday, March 8 (sec. 3)

In questions 1-6 circle the answer options you believe are correct. 
Attach detailed solutions to questions 7-9. In addition, write answers in boxes provided.
STAPLE your work to this answer sheet and hand in to me in class.
Each question is worth 5 marks for the total of 50 for the entire assignment.

Q1: Which compound is not an electrolyte?
 
a) HCl b) Rb2SO4 c) Ar d) KOH e) NaCl

Q2: When H2SO4 is neutralized by KOH in aqueous solution, the net ionic equation is:
 
a) SO42-(aq) + 2 K+(aq) --> K2SO4(aq)
b) SO42-(aq) + 2 K+(aq) --> K2SO4(s)
c) H+(aq) + OH-(aq) --> H2O(l)
d) H2SO4(aq) + 2 OH-(aq) --> 2 H2O(l) + SO42-(aq)
e) 2 H+(aq) + 2 KOH(aq) --> 2 H2O(l) + 2 K+(aq)

Q3: A 0.200M K2SO4 solution is produced by:
 
a) dilution of 250.0 mL of 1.00M K2SO4 to 1.00 L
b) dissolving 43.6 g of K2SO4 in water and diluting to a total volume of 250.0 mL
c) diluting 20.0 mL of 5.00M K2SO4 solution to 500.0 mL
d) dissolving 20.2 g of K2SO4 in water and diluting to 250.0 mL, then diluting 25.0 mL of this solution to a total volume of 500.0 mL
e) dilution of 1.00 mL of 250M K2SO4 to 1.00 L

Q4: What color of visible light has the highest energy?
 
a) blue b) violet c) red d) yellow e) green

Q5: What is the energy of a photon that has a wavelength of 13.2 nm?
 
a) 9.55 x 10-25 J b) 1.62 x 10-17 J c) 1.99 x 10-25 J d) 4.42 x 10-23 J e) 1.51 x 10-17 J

Q6: Which of the combinations of n, l, and ml quantum numbers are permissible (allowed)?
There may be more than one correct answer to this question! Circle all answer options you think are correct.
 
a) 1, 1, 0 b) 3, 2, 1 c) 2, 1, 2 d) 5, 0, -1 e) 4, 1, 0

Provide detailed solutions to questions 7 - 9

Q7: What are the respective molar concentrations (in mol/L) of Na+ and SO42- afforded by dissolving
0.500 mol Na2SO4 in water and diluting to 1.33 L?
 
Answer:

 

Q8: A 17.5 mL sample of acetic acid (CH3COOH) solution required 29.6 mL of 0.250M NaOH for neutralization.
What was the molar concentration of acetic acid?
 
Answer:

 

Q9: It takes 254 kJ per 1 mole of a certain metal to eject electrons from its surface. What is the longest wavelength
of light (nm) that can be used to eject electrons from the surface of this metal via the photoelectric effect?
Hint: Calculate the amount of energy needed to eject an electron from 1 atom first (NA = 6.022 x 1023).
Then proceed to find the frequency of light which carries this energy, and finally find the wavelength of that light.
 
Answer:

Provide answers to question 10 a-c in the appropriate boxes

Q10: Draw balloon pictures of the following orbitals, described below by their quantum numbers (a)
or a symbol (b) and (c).
 
a) n = 1, l = 0, ml = 0
 
 
 
 
 
 
 
 
 
 
 
 

 

 b) 2pz c) 3dxy