(a) How many molecules are present in a sample of an ideal gas that occupies a volume of 1.60 cm³, is at a temperature of 20C, and is at atmospheric pressure?

(b)

How many molecules of the gas are present if the volume and temperature are the same as in part (a), but the pressure is now 2.90 10¹¹ Pa (an extremely good vacuum)?

my last attempt it is. Solve it correctly please. Multiple votes will be given.