Answer:
This formula contains 12 oxygen atoms.
The element in period 4 of the Periodic Table with the highest electronegativity is krypton (2.96).
Answer:
It's a physical property because color is chemically not significant.
But occurance of a flame is chemical property because combustion takes place
Answer: B I think, I'll put my reasoning below.
Explanation:
It's not A because removing N2 would only shift the equation the opposite way.
It's not C and D because I don't think those affect the specific amount of each reactant/product produced. I think temperature only affects the speed at which the reaction is performed, which won't affect anything in this case.
Answer: Hydrogen ion concentration of the lake is 
Explanation:
pH or pOH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration. Acids have pH ranging from 1 to 6.9 and bases have pH ranging from 7.1 to 14.
To calculate the pH of the solution, we use the equation:
We are given:
pH = 4.0
Putting values in above equation, we get:
![[H^+]=10^{-4.0}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D10%5E%7B-4.0%7D)
![[H^+]=10^{-4}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D10%5E%7B-4%7D)
Thus hydrogen ion concentration of the lake is 