The dissociation of formic acid is:

The acid dissociation constant of formic acid,
is:
![k_a = \frac{[HCOO^{-}] [H^{+}]}{HCOOH}](https://tex.z-dn.net/?f=%20k_a%20%3D%20%5Cfrac%7B%5BHCOO%5E%7B-%7D%5D%20%20%5BH%5E%7B%2B%7D%5D%7D%7BHCOOH%7D%20%20%20%20%20)
Rearranging the equation:
![\frac{[HCOO^{-}]}{[HCOOH]} = \frac{k_a}{[H_+]}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5BHCOO%5E%7B-%7D%5D%7D%7B%5BHCOOH%5D%7D%20%3D%20%5Cfrac%7Bk_a%7D%7B%5BH_%2B%5D%7D%20)
pH = 2.75
![pH = -log[H^{+}]](https://tex.z-dn.net/?f=%20pH%20%3D%20-log%5BH%5E%7B%2B%7D%5D%20)
![[H^{+}]= 10^{-2.75} = 1.78 \times 10^{-3}](https://tex.z-dn.net/?f=%20%5BH%5E%7B%2B%7D%5D%3D%2010%5E%7B-2.75%7D%20%3D%201.78%20%5Ctimes%2010%5E%7B-3%7D%20)


Substituting the values in the equation:
![\frac{[HCOO^{-}]}{[HCOOH]} = \frac{k_a}{[H_+]}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5BHCOO%5E%7B-%7D%5D%7D%7B%5BHCOOH%5D%7D%20%3D%20%5Cfrac%7Bk_a%7D%7B%5BH_%2B%5D%7D%20)
![\frac{[HCOO^{-}]}{[HCOOH]} = \frac{1.78\times 10^{-4}}{1.78\times 10^{-3}}](https://tex.z-dn.net/?f=%20%5Cfrac%7B%5BHCOO%5E%7B-%7D%5D%7D%7B%5BHCOOH%5D%7D%20%3D%20%5Cfrac%7B1.78%5Ctimes%2010%5E%7B-4%7D%7D%7B1.78%5Ctimes%2010%5E%7B-3%7D%7D%20%20%20)
Hence, the ratio is
.
Answer:
I don't know 100% but im pretty sure its electrons, if im wrong im really sorry let me know in the comments ill change it
explanation
the nucleus has more weight but its more compact but the electrons are spread apart circling the nucleus and therefor take up more space
Answer: .150 moles of Ana
Explanation:
You just multiply 3.45 g of Na times the number of mole so in this case 1 mole divided by the grams it takes to make that mole. Which can be found on your periodic table it is the number right under the symbol of the element.
Answer: The concentration of hydrogen ion in the given solution is
.
Explanation:
pOH of a solution is the negative logarithm of concentration of hydroxide ions.
Hence, if
is
then its pOH value is calculated as follows.
![pOH = -log [OH^{-}]\\= -log (3.5 \times 10^{-5})\\= 4.45](https://tex.z-dn.net/?f=pOH%20%3D%20-log%20%5BOH%5E%7B-%7D%5D%5C%5C%3D%20-log%20%283.5%20%5Ctimes%2010%5E%7B-5%7D%29%5C%5C%3D%204.45)
Now, the relation between pH and pOH is as follows.
pH + pOH = 14
pH + 4.45 = 14
pH = 14 - 4.45
= 9.55
And, pH is the negative logarithm of concentration of hydrogen ions. Hence,
is calculated as follows.
![pH = -log [H^{+}]\\9.55 = -log [H^{+}]\\H^{+} = 2.81 \times 10^{-10}](https://tex.z-dn.net/?f=pH%20%3D%20-log%20%5BH%5E%7B%2B%7D%5D%5C%5C9.55%20%3D%20-log%20%5BH%5E%7B%2B%7D%5D%5C%5CH%5E%7B%2B%7D%20%3D%202.81%20%5Ctimes%2010%5E%7B-10%7D)
Thus, we can conclude that the concentration of hydrogen ion in the given solution is
.