Yes, I mean Cl-35.
“If you had a sample of pure 35Cl which had no 37Cl, then you could say it had an atomic weight of 35.”
Ok good. You at least know what you are talking about.
“The purpose of using the given atomic mass (35.453) is to accurately know the weight of one mole of chlorine”
You’re switching between atomic weight and atomic mass? Interesting.
Use ‘relative atomic mass’ and ‘atomic mass’. Atomic mass should be almost or exactly the same as ‘mass number’, because that is what they are supposed to represent. That’s why we use the 35 and the 37 as shorthand.
Relative atomic mass is useful, if and only if you are assuming that the sample has the expected ratio. It’s not useful on a periodic table. Nor is it useful when you are trying to determine the experimental ratio between two isotopes of the same element.
Can you understand why assuming that the ratio is going to be the bearing takes away from the understanding that an element is defined by the number of protons it has?
I take it that you have never taken a quantitative analysis class. The 35.453 is the most important number because if you have one mole of chlorine gas, it will weigh 70.906 grams. Not 70 grams. Not 74 grams. But 70.906 grams.
OK. One more lesson in chemistry. Are you getting tired from digging that hole?
Definition: Atomic mass or atomic weight is the average mass of atoms of an element, calculated using the relative abundance of isotopes in a naturally-occurring element.
Also Known As: Atomic Weight