[boostar]

Hi guys, Ima new here. .

Just a few questions: (Excuse the bad equation setting out).

1) What is the percent ionization of the acid in a 0.0005 M solution of choloracetic acid. (ClCh₂CO₂H) (Ka 1.36 e-3)?

I did:

ka = x²
       -------------------
        0.0005 - x

and than x / 0.0005

and ended up with a percent of 77.77%

Could I have some verification if it is right or not please?

2) What volume (in mL) of 0.23 M HCl solution must be added to 300.00 mL of 0.34 M ammonia solution to give a buffer solution with pH 9.50. (Kb for ammonia 1.80 e -5).

Not very sure on this one. I think it is like:

NH₃ + HCl = NH₄Cl   ?

c=n/v
.34=n/.3
Moles of NH₃ = .102 mols

Than use pH = -log kb + log ( acid /salt of acid )  -> Ph     ?

Any help appreciated .

3) What is the new pH if a drop containing 0.001 moles of NaOH is added to 100.00mL of a solution 0.100 M in each of acetic acid and soidum acetate? (Ka for acetic acid 1.75 e-5).

Dunno much about this one either.

c=n/v
c=0.001/.1
c=.01 M of NaOH

4)
If one was discuss the similiarities and unsimiliarities of the group IV elements, what physical chemical properties would be best?

For physical so Far I have:
Melting Point
Boiling Point
Atomic Number
Atomic Weight
Density in Room Temp

I am not sure about electronegativety (Because they Tin and Lead don't have one it seems) and I am not sure about specific gravity.  Any more worth looking in to? And any good sites that would tell the info? I have looked around multiple sites, but results from just one sight gives you at least similar data.

And for chemical properties all I have is Ionisation energy. (Though I am not sure how exactly to compare these).

Anything for chemical properties? My teacher said something about comparing their reactions like:

IV element + O₂
IV element + Cl₂

I am not sure why though and how would I compare them?
 
Again any good sites that would tell the info? I have looked around multiple sites, but results from just one sight gives you at least similar data, unlike large differences.


Thankyou guys, apologies for giant thread, look forward to replies. .

[AWK]

1. Use Ostwald dilution law Ka=c(alpha)²/(1-alpha)
2. Use henderson-Hasselbach equation and stoichiometry of neutralization
[OH^-=Kbx(300x0.34-Vx0.23)/(300x0.34)
V is in cm³
3. NaOH reacts with sodium acetate to form more acetic acid
4. search www.webelements.com

[boostar]

Ty, I am still not sure if I get it but I have some answer at the very least.

Some new questions:

1) How was Mendeleev able to predict some of the properties of Germanium? --> What method? (It must have something to do with group trends).

2)
"The structures change from giant molecular lattices in carbon and silicon to giant metallic lattices in tin and lead, and this is the reason for the changes in physical properties."

Also, what is a distorted close-packed arrangement --> That one is very important.

Would it be possible to find such structures on the net? (It appears not to be on webelements).

3) What would be a good place to start to look into the similarities shared between the elements in gorup 14?

eg. Silicon and Carbon both have diamond structures.