bsbllallstr8

yea... SO3+OH--->HSO4-

jksbond007

i think K units are 1/sec not 1/min

Hecatonchires

No, it is not seconds because the time was given in minutes.

crypto86

yeah - it's 1/min for the units

uofmhopeful

I HAVE ANSWERED QUESTIONS 3, 4, 5, 6, AND 7!


3
a) (i) 1st order with respect to I-
(ii) 1st order ith rspect to ClO-

b) (i) rate=k(I-)(ClO-)
(ii) k= about 611.76 L/(mol)(seconds)

c) (i) natural log of (H2O2)
(ii) units for k is equal to 1/(minutes)
(iii) elongate the line, MAKE SURE IT REACHES THE SAME Y VALUE AS THE GIVEN LINE

4
a) Zn + Ni(2+) ---> Zn(2+) + Ni
c) C2H2 - O2 ---> CO2 + H2O
f) BH3 + NH3 ---> BH3NH3
h) Pb(2+) + I(-) ---> PbI2
FORGOT MY OTHER CHOICE

5
a) Nitrogen condenses, Oxygen drives the flame even more and burns, Hydrogen violently reacts

b) CaO is acidic because metallic oxides form acidic solutions
SiO2 is apparently neutral because it is a tranition metal and will form sand
CO2 is basic because nonmetallic oxides will form basic solutions

c) (i) Ag2S
(ii) KNO3 forms an aqueous solution and AgCl forms a precipitate that isn’t black
(iii) Solution 1=AgNO3
Solution 2=Na2S
Solution 3=Kcl

6
a) If you don’t know these, I hope you fail this exam. However, CF4 creates a tetrahedral shape, PF5 has a trigonal bipyramid shape, and SF4 has a seesaw shape.
b) (i) The bond angle is 109.5 degrees
(ii) The hybridization is sp3d (or dsp3). Either one works.
(iii) Like stated above, a seesaw or distorted tetrahedron.

c) (i) sigma= 4
pi= 1
(ii) I didn’t know what formal charge was, so I just said structure one because phosphorus has 5 valence electrons and the oxygen double bonded to it and the 3 flourines bonded with all five. Structure 2 bonded with only 4 of the 5 valence electrons.

7
a) (i) NH3 enters into hydrogen bonding and NF3 contains London dispersion forces.
(ii) Hydrogen bonds are very strong compared to London dispersion forces, thus NH3 has a higher boiling point.

b) (i) KCl and NaCl both contain London dispersion forces but NaCl forms as a crystalline lattice. This was pretty darn tricky.
(ii) It takes more energy to melt a crystal rather than molecules bonded together with London dispersion forces. So NaCl has a higher melting point.

c) (i) All are at the 3rd energy level, so n=3.
(ii) Chlorine has the most valence electrons an the smallest radius, so it has the greatest pull on electrons, so it has the highest ionization energy. Silicon has the least amount of valence electrons and the largest radius, thus having the weakest pull on the electron, so it has the least ionization energy. Phosphorus is in the middle.

d) I DON’T SEE WHY THERE IS MUCH DEBATE OVER THIS QUESTION. IT IS VERY STRAIGHTFORWARD.
(i) The average of the 2 masses is 63.93, so look at the periodic table and ta-da! Copper ‘s mass is 63.55. Copper is the final answer.
(ii) OK, this is where some don’t understand the question. I will show you in the form of an equation:

Okay, you have the 2 isotopes, right? So, there is a combination of those two that equates to the mass on the periodic table. So, one of them composes “x” percent of the CU mass you see on the periodic table, and the other composes “1-x” percent. So, you can come up with this equation: 62.93(x) + 64.93(1-x) = 63.55
I hope you can do the math, and once you do, you find that x equals .69
So, you can find 69% of the first isotope, and 31% of the second. thus, the first isotope is more abundant.

BUT, if you can understand this question, then you can see that the periodic table mass of copper (63.55) is less than the average mass of the 2 isotopes, so there must be more of the first, less weighing isotope.

IF YOU THINK I SCREWED UP, PLEASE REPLY!!!!!

theleet

nobody did #2?

man_on_fire

Hmm, you might be right, but the answer I put was that the melting points of ionic substances are dependent on the magnitude of the charges and the size of the ions. Magnitude of charges isn't an issue here but NaCl is smaller and closer to the nucleus and thus has a stronger attraction towards it, which accounts for the high melting point.

man_on_fire

Does it matter if you put lnX instead of ln(H2O2)? I just put represented H2O2 as X. Please tell me that is still full credit.

Student

b) CaO is acidic because metallic oxides form acidic solutions
SiO2 is apparently neutral because it is a tranition metal and will form sand
CO2 is basic because nonmetallic oxides will form basic solutions

You sure? I have CaO and CO2 reversed -- check my post on page 5 for reasoning.

rhs06

Student, you are right. Metallic oxides form bases and nonmetallic oxides form acids.

uofmhopeful

student, you are right, i screwed up there. i put what you put on my test, but I just messed up here. Thanks for ointing that out.

CaO + H2O ---> Ca(OH)2

CO2 + H2O ---> H2CO3

crypto86

Yes, rhs06 and student are correct. Also, NaCl and KCl exhibit ionic bonding, not london dispersion forces. And NaCl has a higher melting point than KCl due to the greater ionic forces as calculated by Coulomb's Law. Since the distance between the center of each ion (Na+ and Cl-) is less than K+ and Cl-, then when you plug in the distance (radius) into Coulomb's Law - F = Q1Q2/r^2 - the radius^2 term is smaller for NaCl, and when a denominator is smaller the entire value is larger. Since the intramolecular forces are larger in NaCl, it has a higher melting point.

uofmhopeful

Crypto, london dispersion forces are a segment of ionic bonding. NaCl forms as a crystalline lattice, and is stronger than the london dispersion force found in KCl.

rhs06

crypto, that's exactly what I put

uofmhopeful

aren't london dispersion forces th weakest form of ionic bonding????