Question

NO OF MOLECULES PRESENT IN 8g OF KNO3!?

Answer 1

mass of kno3 = 39+14+16*4=35+64=98 g
molecules in 98 g kno3= 6.022*10^23
8g =8/98 moles kno3
no. of molecules= 6.022*10^23 * 8/98 = 4.91*10^22

Answer 2

Molar mass of K = 39
N = 14
O3 = 16 × 3 = 48

=> Molar mass of KNO3 = 39 + 14 + 48

=> Molar mass of KNO3 = 101

So moles = weight (grams)/molar mass

= 8/101

Now we know that,

No. of molecules/ Avogadro Number = moles

=> No. of molecules = moles × Avogadro number

=> No. of molecules = 8/101 × 6.022 × 10²³

=> No. of molecules = 0.476 × 10²³ (approx)

or, = 4.76 × 10²² (approx)