Amothball, composed of naphthalene (c10h8), has a mass of 1.98 g . how many naphthalene molecules does it contain?

Carbon's mass number =12
Hydrogen's mass number=1
( 10×12)+(8×1)
=128
128g =1mol

1.98g ?

1.98
=0.015
128

1mol =6.0×10^23

0.015mol ?

0.015mol×6.0×10^23= 9×10^21

Thus the number of particles in 1.89 grams of napthalene is 9×10^21.

I sincerely hope this is correct.

Ethene molecular fórmula= c2h4molecular weight = 29.046g/molhope it : )