Moles = mass/molar mass
moles = 2.3
molar mass = 278
=> mass = moles*molar mass = 639.4g
Your answer is B: The outer electron of Adam B has moved to a higher energy state
Smaller atoms and stronger bonds promotes greater hardness in minerals.
Explanation:
Charges on both magnesium and oxygen is 2. Though opposite in sign, they have equal charges so, both of them will be cancelled by each other.
As a result, formula of magnesium oxide is MgO and not
.
The student write the equation as
, it is not correct.
Therefore, given equation will be balanced as follows.

Since, number of atoms on both reactant and product side are equal. Hence, this equation is completely balanced.