Answer:
I say the second one, im not rlly sure tho
Explanation:
Answer: Its average atomic mass is 114.9 amu
Explanation:
Mass of isotope 1 = 113 amu
% abundance of isotope 1 = 5% = 
Mass of isotope 2 = 115 amu
% abundance of isotope 2 = 95% = 
Formula used for average atomic mass of an element :

![A=\sum[(113\times 0.05)+(115\times 0.95)]](https://tex.z-dn.net/?f=A%3D%5Csum%5B%28113%5Ctimes%200.05%29%2B%28115%5Ctimes%200.95%29%5D)

Thus its average atomic mass is 114.9 amu
Answer: to calculate pH use -log[H+] or - log[OH-]..the solution is basic as the “NaOH” is attached to a hydroxide.Since we need to find the pH (per hydrogen) and not the pOH( per hydroxide) we need to find the pOH of the substance first then we subtract that by 14 so we can arrive at the pH of the substance.
Explanation: So -log( 1 x 10^(-5)) = 5 which is the pOH.Now we subtract that by 14 which gives us -9 and now you’d multiply that by -1 bcuz we can’t have a negative so the pH of the substance is 9