Answer:
The answer is 4.28 moles
Explanation:
This is super easy okay, you won't forget this!
Basically mole ratios, we're just looking at the coefficients in front of the compounds, multiplying them, and dividing them as we see fit.
In this example, you can see how you need 2 moles of lithium bromide (LiBr) for the reaction, and 2 moles of lithium chloride (LiCl) will be produced.
Basically, the <u>molar ratio</u> is when you divide numbers and see how much of this do I have for that (if that makes sense).
So if you were to divide the 2 moles of LiBr / 2 moles of LiCl = 1. So we know that the mole ratio for LiBr to LiCl is 1:1 or 2:2, either or, it's the same thing.
SO THE BIG IDEA, if we have 4.28 moles of lithium bromide reacting, we should also have 4.28 moles of lithium chloride produced, BECAUSE the <u>mole ratio</u> is 1:1.
I hope this makes sense please tell me if it doesn't, I will try my best to explain a little more.
Answer: Total number of Protons PLUS Neutrons
Explanation:
Hopes that helps
The answer is the first one I think
Amount of silver nitrate taken = 269.μmol 
Volume of the solution = 300. mL
Concentration of a solution is generally expressed in terms of molarity. Molarity is defined as the moles of a substance present per liter of the solution.

We want the concentration in millimoles/L.
Converting μmol to millimol solute:
μ
= 0.269 millimol
Volume from mL to L: 
Therefore concentration of the chemist's solution = 
Not sure about the first two but I think number three is B. sorry if I'm wrong