How many atoms in the formula Be (NO3)2
1 answer:
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Answer :
The correct answer for primary component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
<u>Buffer solution :</u>
It is a solution of mixture of weak acid and its conjugate base OR weak base and its conjugate acid . It resist any change in solution when small amount of strong acid or base is added .
<u>Capacity of a good buffer : </u>
A good buffer is identified when pH = pKa .
From Hasselbalch - Henderson equation which is as follows :
If [A⁻] = [HA] ,
pH = pka + log 1
pH = pKa
This determines that if concentration of weak acid and its conjugate base are changed in small quantity , the capacity of buffer to maintain a constant pH is greatest at pka . If the amount of [A⁻] or [HA] is changed in large amount , the log value deviates more than +/- 1M and hence pH .
Hence Buffer has best capacity at pH = pka .
<u>Phosphate Buffer : </u>
Phosphate may have three types of acid-base pairs at different pka ( shown in image ).
Since the question is asking the pH = 7.4
At pH = 7.4 , the best phosphate buffer will have pka near to 7.4 .
If image is checked the acid - base pair " H₂PO₄⁻ and HPO₄²⁻ has pka 7.2 which is near to pH = 7.4 .
Hence we can say , the primary chemical component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
Answer:
The answer to the question is;
The equilibrium constant for the reaction is 0.278
Reversibility.
Explanation:
Initial concentration = 0.500 M N₂ and 0.800 M H₂
N₂ (g) + 3·H₂ (g) ⇔ 2·NH₃ (g)
One mole of nitrogen combines with three moles of hydrogen form 2 moles of ammonia
That is 1 mole of ammonia requires 3/2 moles of H₂ and 1/2 moles of N₂
0.150 M of ammonia requires 3/2×0.150 moles of H₂ and 1/2×0.150 moles of N₂
That is 0.150 M of ammonia requires 0.225 moles of H₂ and 0.075 moles of N₂
Therefore at equilibrium we have
Number of moles of Nitrogen = 0.500 M - 0.075 M = 0.425 M
Number of moles of Hydrogen = 0.800 M - 0.225 M = 0.575 M
Number of moles of Ammonia = 0.150 M
K =
= 0.278
The kind of reaction is a reversible one as the equilibrium constant is greater than 0.01 which as general guide, all components in a reaction with an equilibrium constant between the ranges of 0.01 and 100 will be present when equilibrium is reached and the chemical reaction will be reversible.