If the number of particles in a mole is 6.022x1023, what is the total mass of 1.81*1024 particles of nitrogen gas (N2) ?

A. 42 g

B. 4.2 g

C. 84 g

D. 8.4 g

the total mass of 1.81 x10^24 particle nitrogen gas is calculated as follows

find the moles of nitrogen

1 moles = 6.022 x10 ^23 particles

what about 1.81 x10^23 = ? moles

= (1.81 x10^ 24) / (6.022 x10^23) = 3 moles

mass = moles x molar mass of nitrogen gas = 14 x2 = 28 g/mol

= 3 moles x28 g/mol = 84 grams