The valence electrons should be the correct answer
Answer: 106.905
Explanation: If there are only 2 isotopes, and 1 of them is 48.16%, the second must, by default, be (100 - 48.16%) = 51.84% The final, averaged, atomic mass is 107.868. This is made up of each isotope's atomic mass times the percentage of that isotope in the total sample. The weighted value of the known isotope (109) plus that of the unknown must come to the observed value of 107.868 amu. (107.868 - 52.45 = 55.42). Divide that by the % for that isotope (55.42/0.5184) = 106.90 amu for the second isotope.
<u>Atomic Mass</u> <u>% of Sample</u> <u>Weighted Value</u>
108.905 48.16% 52.45
X 51.84% <u>55.42</u>
107.87
X = (55.42/0.5184) = 106.90 amu
one mole
If we look this number up for helium, we find that helium has a molar mass of 4.0 grams per mole. So one mole of helium has a mass of 4.0 grams. We can use the molar mass as a conversion factor. Two moles of helium times four grams of helium per mole of helium is equal to eight grams of helium.
Hi there!
The answer would be D. Forming or breaking bonds.
When forming or breaking bonds, a new substance is created and it’s no longer just a physical change. Sometimes when bonds are breaking and new ones are forming there can be a change in composition.
Hope this helps !
