Answer:
See explanation
Explanation:
The mole refers to the amount of substance contained in 12 g of carbon-12. It was arbitrarily related to the number of elementary entities in 12 g of carbon -12 by Prof. Avogadro.
The number of moles of a substance is obtained as the mass of the substance divided by the mass of one mole of the substance (molar mass). Hence when the number of moles is known, the mass is now;
number of moles * molar mass
Answer : The average atomic mass of an element X is, 63.546 amu
Solution : Given,
Mass of isotope X-63 = 62.9296 amu
% abundance of isotope X-63 = 69.15% = 0.6915
Mass of isotope X-64 = 64.9278 amu
% abundance of isotope X-64 = 30.85% = 0.3085
Formula used for average atomic mass of an element X :
Therefore, the average atomic mass of an element X is, 63.546 amu
Answer:

Explanation:
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In this case, according to the rules for the oxidation states in chemical reactions, it is possible to realize that lone elements have 0 and since magnesium is in group 2A, it forms the cation Mg⁺² as it loses electrons and oxygen is in group 6A so it forms the anion O⁻²; therefore resulting oxidation numbers are:

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