HELP QUICK An unknown substance is a liquid and is red in color.
1 answer:
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Answer:
The greatest acceleration when the unbalanced force is applied will be experienced in :
A) The box with a mass of 2 kg
Explanation:
According to second law of motion the external unbalanced force is directly proportional to rate of change of momentum.
F = (Final momentum - initial momentum)/time
or
Force is equal to the product of mass and acceleration
F = m x a
Here a= acceleration
m = mass of the object
If Force is constant then acceleration is inversely proportional to mass
A) The box with a mass of 2kg
F = 8 N
a = 4 m/s2
B) The box with the mass of 4kg
a = 2 m/s2
C) The box with a mass of 6kg
a = 1.33 m/s2
D) The box with a mass of 8kg
a = 1 m/s2
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⁻ .
