The total charge in coulombs on 19 g of (PO4) ^ 3- ion is :
 
 
a) 6.02 x 10^23
 
b) 1.8 x 10^3
 
c) 5.79 x 10^3
 
d) 57.9

Asked by Balbir | 22nd Aug, 2016, 10:20: PM

Expert Answer:

Molar mass of PO43- = 95 g / mole

PO43- means atom has gained 3 electrons. We will first calculate the mass of these 3-electrons.

Gained mass = 3 x 9.1091x10-28 (mass of electron) x 6.022x1023 (Avogadro's constant) = 0.00164565 g / mole.

Molar mass of PO43- = 95 g / mole

19 g of PO43- means = 19 / 95 moles = 0.2 moles.

Ions in 0.2 moles = 0.2 x 6.022 x 1023 = 1.2044 x 1023 ions.

Charge on each ion = 3 x 1.602 x 10-19 = 4.806 x 10-19 coulombs.

So, charge of 19g of PO43-ions = 1.2044 x 1023 x 4.806 x 10-19 coulombs = 5.78 x 104 Coulombs.

 

Answered by Vaibhav Chavan | 23rd Aug, 2016, 01:35: PM