Answer:
Explanation:
To calculate pH you need to use Henderson-Hasselbalch formula:
pH = pka + log₁₀ ![\frac{[A^-]}{[HA]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BA%5E-%5D%7D%7B%5BHA%5D%7D)
Where HA is the acid concentration and A⁻ is the conjugate base concentration.
The equilibrium of acetic acid is:
CH₃COOH ⇄ CH₃COO⁻ + H⁺ pka: 4,75
Where <em>CH₃COOH </em>is the acid and <em>CH₃COO⁻ </em>is the conjugate base.
Thus, Henderson-Hasselbalch formula for acetic acid equilibrium is:
pH = 4,75 + log₁₀ ![\frac{[CH_{3}COO^-]}{[CH_{3}COOH]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BCH_%7B3%7DCOO%5E-%5D%7D%7B%5BCH_%7B3%7DCOOH%5D%7D)
a) The pH is: 
pH = 4,75 + log₁₀ ![\frac{[2 mol]}{[2 mol]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5B2%20mol%5D%7D%7B%5B2%20mol%5D%7D)
<em>pH = 4,75</em>
<em></em>
b) The pH is:
pH = 4,75 + log₁₀ ![\frac{[2 mol]}{[1mol]}](https://tex.z-dn.net/?f=%5Cfrac%7B%5B2%20mol%5D%7D%7B%5B1mol%5D%7D)
<em>pH = 5,05</em>
<em></em>
I hope it helps!
 
        
             
        
        
        
69.9%
Explanation:
To find the mass percentage of iron in the compound in Fe₂O₃, we would go ahead to express the given molar mass of the iron to that of the compound. 
  Mass percentage  =  x 100
  x 100
Molar mass of Fe = 55.85g/mol
Molar mass of O = 16g/mol
Molar mass of Fe₂O₃ = 2(55.85) + 3(16) = 159.7g/mol
 Mass percentage  =  = 69.94% = 69.9%
   = 69.94% = 69.9%
learn more: 
Mass percentage brainly.com/question/8170905
#learnwithBrainly
 
        
             
        
        
        
Answer:
The light is most intense where it strikes Earth _ directly_______ to its surface.
Explanation:
Hope this helps :)
 
        
                    
             
        
        
        
Answer : The mass of nitric acid is, 214.234 grams.
Solution : Given,
Moles of nitric acid = 3.4 moles
Molar mass of nitric acid = 63.01 g/mole
Formula used :

Now put all the given values in this formula, we get the mass of nitric acid.

Therefore, the mass of nitric acid is, 214.234 grams.
 
        
             
        
        
        
Answer:-  The natural abundance of  is 0.478 or 47.8% and
 is 0.478 or 47.8% and  is 0.522 or 52.2% .
 is 0.522 or 52.2% .
Solution:- Average atomic mass of an element is calculated from the atomic masses of it's isotopes and their abundances using the formula:
Average atomic mass = mass of first isotope(abundance) + mass of second isotope(abundance)
We have been given with atomic masses for  and
 and  as 150.919860 and 152.921243 amu, respectively.  Average atomic mass of Eu is 151.964 amu.
 as 150.919860 and 152.921243 amu, respectively.  Average atomic mass of Eu is 151.964 amu. 
Sum of natural abundances of isotopes of an element is always 1. If we assume the abundance of  as n then the abundance of
 as n then the abundance of  would be 1-n .
 would be 1-n .
Let's plug in the values in the formula:

151.964=150.919860n+152.921243-152.921243n
on keeping similar terms on same side:


negative sign is on both sides so it is canceled:



The abundance of  is 0.478 which is 47.8%.
 is 0.478 which is 47.8%.  
The abundance of  is =
 is = 
= 0.522 which is 52.2%
Hence, the natural abundance of  is 0.478 or 47.8% and
 is 0.478 or 47.8% and  is 0.522 or 52.2% .
 is 0.522 or 52.2% .