FeSO₄*7H₂O(s) = FeSO₄(s) + 7H₂O(g)
M(FeSO₄*7H₂O)=278.0 g/mol
M(FeSO₄)=151.9 g/mol
m(FeSO₄*7H₂O)/M(FeSO₄*7H₂O)=m(FeSO₄)/M(FeSO₄)
m(FeSO₄)=M(FeSO₄)m(FeSO₄*7H₂O)/M(FeSO₄*7H₂O)
m(FeSO₄)=151.9*100.0/278.0=54.6 g
m(FeSO₄)=54.6 g
As it is located at 7s ^2 it will have 2 valence electrons that due to its position in the s orbital it will be prone to losing them to obtain a noble gas configuration.
B. False. An alpha particle is a Helium nucleus which has a mass of 4 as it is made from 2 neutrons and protons each with mass of +1.
Answer:
Coefficient in front of the 
in the balanced equation - 4
Explanation:
The unbalanced reaction is shown below as:-
On the left hand side,
There are 1 nitrogen atom and 3 hydrogen atoms and 3 oxygen atoms
On the right hand side,
There are 1 nitrogen atom and 2 hydrogen atoms and 2 oxygen atoms
Thus,
Right side, 
must be multiplied by 6 and by 4
Left side, 
is multiplied by 5 and 
by 4 so to balance the whole reaction.
Thus, the balanced reaction is:-
<u>Coefficient in front of the in the balanced equation - 4</u>
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