<u>Answer:</u> The hydrogen ion concentration of his saliva is 
<u>Explanation:</u>
pH is defined as the negative logarithm of hydrogen ion concentration present in the solution.
To calculate the pH of the solution, we use the equation:
![pH=-\log[H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D)
We are given:
pH of the saliva = 6.1
Putting values in above equation, we get:
![6.1=-\log[H^+]](https://tex.z-dn.net/?f=6.1%3D-%5Clog%5BH%5E%2B%5D)
![[H^+]=10^{-6.1}=7.94\times 10^{-7}M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D10%5E%7B-6.1%7D%3D7.94%5Ctimes%2010%5E%7B-7%7DM)
Hence, the hydrogen ion concentration of his saliva is
Answer:
A Beaker, however if you are doing this from home a measuring cup would probably be more available.
Three ways water reaches from earth to atmosphere are
1. direct evaporation from the water bodies like sea,river,oceans
2. moisture from the land(you must have seen land dries out)
3.moisture from the plant(small capillaries from the plants sucks water from land n goes to atmosphere in form of vapour from leaves)
Air is a mixture because it is made up of many constituents like oxygen, argon etc. it can be physically separated by fractional distillation. it doesnt have a formula unlike compounds and elements. its composition varies differently with its constituents.
