Answer:
Explanation:
This is the answer it all done in order i hope this helps tell em if u dont understnad it
A scientific control is an experiment or observation designed to minimize the effects of variables other than the independent variable.
There are 6.022*10^23 molecules in 1 mole of carbon
So how many will moles will be 7.87*20^7?
Let the required number of moles be ‘x’.
1 mole ———6.022*10^23
x moles———7.87*10^7
(Cross multiplication)
x=7.87*10^7/6.022*10^23
Therefore x=1.3*10^-16
Answer:
pH of the solution = 9.45
Explanation:
pKb = 8.57
pKb = -logKb
Kb = antilog pkb

ICE table for the ionization of pyrodine is:

initial 0.435 0 0
equi. 0.435 - x x x
so,
![k_b =\frac{ [C_5H_5NH^+][OH^-]}{[C_5H_5N]}\\1.78\times 10^{-9}=\frac{x^2}{0.453 - x}](https://tex.z-dn.net/?f=k_b%20%3D%5Cfrac%7B%20%5BC_5H_5NH%5E%2B%5D%5BOH%5E-%5D%7D%7B%5BC_5H_5N%5D%7D%5C%5C1.78%5Ctimes%2010%5E%7B-9%7D%3D%5Cfrac%7Bx%5E2%7D%7B0.453%20-%20x%7D)
As kb is very less that means there is very less ionization, hence x can be ignored as compared to 0.435

pOH = -log[OH-]
![pOH = -log[2.78\times 10^{-5}]\\=4.55](https://tex.z-dn.net/?f=pOH%20%3D%20-log%5B2.78%5Ctimes%2010%5E%7B-5%7D%5D%5C%5C%3D4.55)
pH = 14 - pOH
= 14 - 4.55
= 9.45