Answer :
We must find the moles => n
First, we assume ideal gas conditions, so we can use the ideal gas law:
[tex]p\text{ x V = n x R x T (1)}[/tex]p = pressure in atm
V = volume in L
n = moles = needs to be found
T = temperature in K, to get Kelvin we must do this procedure:
T (°C) + 273 = T (K)
68 °C + 273 = 341 K
R = gas constant = 0.082 atm x L / mol x K, we take this value of R because of the units we already have.
Procedure:
Clear "n" from (1)
[tex]\begin{gathered} \frac{p\text{ x V}}{R\text{ x T}}=\text{ n} \\ \frac{9.3\text{ atm x 19.8 L}}{0.082\text{ }\frac{atm\text{ L}}{\text{mol K}}\text{ x 341 K}}=\text{ 6.6 moles (approx.) = n} \end{gathered}[/tex]Answer: n = 6.6 moles