How can we choose the best chemicals to create a cold or hot pack?
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The Molecule of Sodium Formate along with Formal Charges (in blue) and lone pair electrons (in red) is attached below.
Sodium Formate is an ionic compound made up of a positive part (Sodium Ion) and a polyatomic anion (Formate).
Nomenclature:
In ionic compounds the positive part is named first. As sodium ion is the positive part hence, it is named first followed by the negative part i.e. formate.
Name of Formate:
Formate ion has been derived from formic acid ( the simplest carboxylic acid). When carboxylic acids looses the acidic proton of -COOH, they are converted into Carboxylate ions.
E.g.
HCOOH (formic acid) → HCOO⁻ (formate) + H⁺
H₃CCOOH (acetic acid) → H₃CCOO⁻ (acetate) + H⁺
Formal Charges:
Formal charges are calculated using following formula,
F.C = [# of Valence e⁻] - [e⁻ in lone pairs + 1/2 # of bonding electrons]
For Oxygen:
F.C = [6] - [6 + 2/2]
F.C = [6] - [6 + 1]
F.C = 6 - 7
F.C = -1
For Sodium:
F.C = [1] - [0 + 0/2]
F.C = [1] - [0]
F.C = 1 - 0
F.C = +1
Answer:
20619.4793 years
Explanation:
The half life of carbon-14 = 5730 years
The formula for the half life for a first order kinetic reaction is:
Where,
is the half life
k is the rate constant.
Thus rate constant is:
5730 years=ln(2)/k
k = 1.21×10⁻⁴ years ⁻¹
Using integrated rate law as:
Where,
is the concentration at time t
is the initial concentration
Given that the final concentration contains 8.25 % of the original quantity which means that:
So,
ln(.0825)= -1.21×10⁻⁴×t
<u> t = 20619.4793 years</u>
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