Chapter 15 homework

I am having trouble with #5. I assumed the answer to be Cu and Pb because all of the compounds listed have the same number of ions. The Cu and Pb have the smallest Ksp value but that answer is wrong.

Acid Base HW Q 19

I have been failing at this question for the past hour...

What is the pH at the equivalence point in

the titration of 20.0 mL of 0.200 M HA with

0.200 MNaOH? The Ka for HA is 5.04×10−6.

I know that at equilibrium there should be equal moles of acid and base. I also know that you have to use a "Kb" equation at equilibrium because the hasselhoff equation doesnt work, which is what i wrote down in my notes. Unfortunately, I can't figure out exactly what to do...

Resonance Structures

Do possible resonance structures of molecules have to follow the octet rule?

Take Home Test-- Various Questions

Mr. Holden,

Few questions here about the test....

1) On the first page that is devoted to stoich (for the most part), you say that there are 7.2L of CO2 at standard conditions. I use the standard conversion of 22.4 L/mol for standard conditions. Am i correct in assuming this?

2) When you are given a reaction with gases and you are given concentrations, can you just use the concentrations as if you were given a reaction with liquids and aqueous solutions in order to find the equilibrium constant?

thanks...

K equilibrium Lab

I do not understand the directions for the second post-lab calculation and analysis question. I graphed my data and it came to be linear. Then I drew a line of best fit. I do not understand how to determine the FeSCN2+ concentrations through the directions given in question 2.

I also think my numbers are messed up. For example, my results for data table 3 were 4.2x10^-4 M (FeSCN2+)eq, 5.8x10^-4 M (Fe3+)eq and .0016 M (SCN-)eq. When i solved for the K values in data table 3 with the equation K= Products/Reactants, my K value came around to 452. That seems a little off.....

Anyone have any suggestions or examples of what they think the correct data is?

-Mike

Weather Conditions

As schools have been closed tomorrow, the test is now scheduled for Tuesday when we return. The lab will be performed on Friday. Monday we'll be learning new material. I'll pass out the take home test on Friday, and I'll email it to anyone who needs it. Please email me so I can respond with the test.

Mr. Holden

Test 2/11

Mr Holden,

I wont be in school on friday, and there is a 2 hr delay so what is the test situation tomorrow?

thanks