Answer:
One
Explanation:
An element is a pure substance in which there are only one kind of atom. Elements are distinct substances that cannot be split up into simpler substances.
Such substances consists of only one kind of atom. There are over a hundred known elements to date.
Generally, as a pure substance, the composition of an element is definite and they are homogenous in all parts.
Water goes into the sky by condensation I think
Answer:
a) Kb = 10^-9
b) pH = 3.02
Explanation:
a) pH 5.0 titration with a 100 mL sample containing 500 mL of 0.10 M HCl, or 0.05 moles of HCl. Therefore we have the following:
[NaA] and [A-] = 0.05/0.6 = 0.083 M
Kb = Kw/Ka = 10^-14/[H+] = 10^-14/10^-5 = 10^-9
b) For the stoichiometric point in the titration, 0.100 moles of NaA have to be found in a 1.1L solution, and this is equal to:
[A-] = [H+] = (0.1 L)*(1 M)/1.1 L = 0.091 M
pKb = 10^-9
Ka = 10^-5
HA = H+ + A-
Ka = 10^-5 = ([H+]*[A-])/[HA] = [H+]^2/(0.091 - [H+])
[H+]^2 + 10^5 * [H+] - 10^-5 * 0.091 = 0
Clearing [H+]:
[H+] = 0.00095 M
pH = -log([H+]) = -log(0.00095) = 3.02
Answer:
785
Explanation:
Molecular. X. W
Weight
8000-16000 0.05 0.03
16000-24000. 0.017. 0.08
24000-32000. 0.22. 0.18
32000-40000. 0.25. 0.35
40000-48000. 0.22. 0.27
48000-56000. 0.09. 0.09
Mean weight X*M. W*M
12000. 600. 240
20000. 3200. 2000
28000. 6720. 5600
36000. 10080. 10800
44000. 8800. 11880
52000. 3640 3640
Total=33040g\mol 36240
Note before repeat molecular weight m= 3*12.01+6*1.008=
42.08g/mol
Degree of polymerization= total W*M/w=33040/42.08 =785
