Question

the number of atoms in 0.05g of hydrogen will be

Answer 1

No. of particles = (given mass/molar mass) * Avogadro No.
Given mass = 0.05 g
Molar mass oh H = 1 g
Therefore no. of particles = (0.05/1) * No
                                          = 0.05 * 6.022*1023
                                          = 0.3011 * 1023
                                                       = 3.011 * 1022 particles

Hope this helps!