Oxygen atoms have six outer electrons Write the symbol for an oxide ion.
1 answer:
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Explanation:
We have to calculate value.
It is known that at the equivalence point concentration of acid is equal to the concentration of anion formed.
Hence, [HA] =
Now, relation between and pH is as follows.
pH =
Putting the values into the above formula as follows.
pH =
4.23 = (as [HA] =
)
= 4.23 (as log (1) = 0)
or, = 4
Thus, we can conclude that of given weak acid is 4.
Answer:
Explanation:
Let A₀ = the original amount of ⁵⁵Co .
The amount remaining after one half-life is ½A₀.
After two half-lives, the amount remaining is ½ ×½A₀ = (½)²A₀.
After three half-lives, the amount remaining is ½ ×(½)²A₀ = (½)³A₀.
The general formula for the amount remaining is:
A =A₀(½)ⁿ
where n is the number of half-lives
n = t/t_½
Data:
A = 1.90 ng
t = 45 h
t_½ = 18.0 h
Calculation:
(a) Calculate n
n = 45/18.0 = 2.5
(b) Calculate A
1.90 = A₀ × (½)^2.5
1.90 = A₀ × 0.178
A₀ = 1.90/0.178 = 10.7 ng
The original mass of ⁵⁵Co was .