Question

find the number of moles in 87 g of K2SO4. (atomic mass of K=39,S =32, O =16)

Answer 1

molecular mass of K2SO4 = 39*2+32+16*4 = 78+32+64= 174g
174 g of K2SO4 contains = 1 mole
87 g of K2SO4 contains = 87 / 174 2 = 0.5 moles ANS...

Answer 2

Given: 87g of potassium sulfate.

To find: We have to find the number of moles.

Solution:

The formula of potassium sulfate is $K_2SO_4$.

The atomic mass of K is 39, sulfur is 32 and the atomic mass of Oxygen is 16.

Hence the molecular mass of potassium sulfate is 39×2+32+16×4=174.

174g of potassium sulfate occupy one mole.

Thus 87g of potassium sulfate will occupy 87/174=0.5 moles.

87g of potassium sulfate has 0.5 moles.