Question

How many grams of neon will have the same number of atoms as 4g of calcium?

Answer 1

same no of atom means same no of mole .
we know ,
mole = given weight /molecular weight
given,
weight of calcium =4g
molecular weight =40g
now,
mole =4/40 =0.1

now ,
mole of neon = 0.1
weight of neon /molecular weight of neon =0.1

molecular weight of neon =20g

hence,
weight of neon/20=0.1

weight of neon =2 g

Answer 2

Number of particles in 4 g of Ca,

= 4/40×6.022×10²³

= 6.022×10²² atoms

Therefore, number of atoms of Ne same as 4 g of Ca

= 20×6.022×10²²/6.022×10²³

=20/10

=2 g