Answer :
Lewis-dot structure : It shows the bonding between the atoms of a molecule and the unpaired electrons present in the molecule.
The given molecule is, 
Beryllium has '2' valence electrons and fluorine has '7' valence electrons. Beryllium is the central atom and fluorine is the terminal atom.
Total number valence electrons in = 2 + 2(7) = 16
According to the Lewis-dot structure, there are '4' number of bonding electrons and 12 number of non-bonding electrons (lone-pair).
The Lewis-dot structure is shown below.
Answer:
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Explanation:
As given
60 min = 50 gm (1)
then we know half-life mean half amount decay time
so we can write as the half of 200 is 100 gm hence
T 1/2 = 100 (2)
solving these two equation by cross multiplication we will get
T 1/2 = 120 min
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Answer:
The mass percent of Al(OH)₃ is 15.3%
Explanation:
The reaction is:
Al(OH)₃ + 3HCl = AlCl₃ + 3H₂O
The excess acid is neutralized with a solution of sodium hidroxide, in the reaction:
NaOH + HCl = NaCl + H₂O
The total moles of HCl is:
From the second titration, the moles of excess of HCl is:
The difference between the total and excess of HCl, it can be know the moles that reacts with the aluminum hydroxide, is:
The ratio between HCl and Al(OH)₃ is 3:1. The MW for aluminum hydroxide is 78 g/mol, thus:
The percentage of Al(OH)₃ is:
%
