A buffer solution is composed of 4.00 4.00 mol of acid and 3.25 3.25 mol of the conjugate base. If the p K a pKa of the acid is 4.70 4.70 , what is the pH of the buffer?

The pH of the buffer is 4.61

Explanation:

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

We are given:

= negative logarithm of acid dissociation constant of weak acid = 4.70

= moles of conjugate base = 3.25 moles

 = Moles of acid = 4.00 moles

pH = ?

Putting values in above equation, we get:

Hence, the pH of the buffer is 4.61

the product of the pressure and volume is also constant

the density of gold = 19.3 g/cm3

the relation between density and mass and volume is

density = mass / volume

given :

mass of gold = 13 g

density = 13g / volume = 19.3

volume = 13 /19.3 = 0.67 cm^3

thus volume of gold nugget = 0.67 cm^3