Question

Mass of one atom of an element is 6.645 × 10^-23 g. How many moles of element are there in 0.320 kg?

Answer 1

Mass of one atom of an element = 6.645 × 10^-23 g = Atomic mass. 

Mass of given element = 0.320 kg

Number of moles = Mass/ Atomic mass 

= (0.320 x 1000)g / (6.645 x 10^-23)g

= (320 x 10²³) / 6.645

= 48.156 x 10²³

= 4.8156 x 10²⁴ moles.

= 48.156 x 10^-23 

= 4.8156 x 10^-24 moles.