I just took the test it is A hope this helps :)
Answer:
Element
Explanation:
Two of the same element may have differing numbers of neutrons, however, when it comes to protons, two of the same element will always have the same number of protons. Two different elements may have the same neutrons, but never protons.
3,91·10²⁴ = 39,1·10²³
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110,96g ----------- 6,02·10²³ molecules
Xg ------------------ 39,1<span>·10²³ molecules
X = (110,96</span>×39,1·10²³)/<span>6,02·10²³
<u>X = 720,687g</u>
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