I think the number of protons in the nucleus the number of valence electrons atomic mass...
Each element absorbs light at specific wavelengths unique to that atom. When astronomers look at an object's spectrum, they can determine its composition based on these wavelengths.
Not sure if this is 100% but I hope it helps.
The estimation of the acidic and the basic character of a solution is called and defined by the pH. The ![\rm [H^{+}]](https://tex.z-dn.net/?f=%5Crm%20%5BH%5E%7B%2B%7D%5D)
concentration of the solution will be 
<h3>What is the pH?</h3>
pH is a measurement of the free hydrogen and hydroxyl ions in the solution of the substance.
It can be calculated as:
![\rm pH = - \rm log[H^{+}]](https://tex.z-dn.net/?f=%5Crm%20pH%20%20%3D%20-%20%5Crm%20log%5BH%5E%7B%2B%7D%5D)
Given,
pH = 3.75
Substituting values in the equation:
![\begin{aligned}\rm 3.75 &= -\rm log[H^{+}]\\\\\rm [H^{+}] &= 10^{-3.75}\\\\&= 1.7782 \times 10^{-4}\end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%5Crm%203.75%20%26%3D%20-%5Crm%20log%5BH%5E%7B%2B%7D%5D%5C%5C%5C%5C%5Crm%20%5BH%5E%7B%2B%7D%5D%20%26%3D%2010%5E%7B-3.75%7D%5C%5C%5C%5C%26%3D%201.7782%20%5Ctimes%2010%5E%7B-4%7D%5Cend%7Baligned%7D)
Therefore, 
is the concentration of the hydrogen ions.
Learn more about pH here:
brainly.com/question/10285267
Answer:
The new pressure exerted by the He, is 1266.6 Torr
Explanation:
A typical problem of gases where the volume is increased and the moles and T° keeps on constant. This is an indirect proportion because when the volume of the flask is increased, pressue decreases because molecules collide to a lesser extent with the walls of the vessel.
P₁ . V₁ = P₂ . V₂
760 Torr . 5L = P₂ . 3L
P₂ = (760 Torr . 5L) / 3L
P₂ = 1266.6 Torr
