a$)$ How many molecules are present in a sample of an ideal gas that occupies a volume of $1\mathrm{.}80$ cm$3,$ is at a temperature of $20\backslash$deg C$,$ and is at atmospheric pressure? molecules $($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 $3\mathrm{.}001011$ Pa $($an extremely good vacuum$)?$ molecules