Question

Calculate the number of moles for the following. 

i) 52 g of He (finding mole from mass).

ii) 12.044 × 10₂₃ number of He atoms (finding mole from number of particles).

Answer 1

i) Atomic mass of He =4g

  Number of moles = \(\frac{Given\, mass}{Molar\,mass} = \frac{52}{4}=13\)

ii) N₀ = 6.022 x 10²³ ; N = 12.044 x 10²³     

Number of moles = \(\frac{N}{N_0}= \frac{12.044\,\times\, 10^{23}}{6.022\,\times\,10^{23}}=2\)