Step-by-step explanation:
To answer this question, we will use the Clapeyron equation.
The Clapeyron equation is a mathematical expression proposed by the French physicist-chemist and civil engineer Benoit-Pierre-Émile Clapeyron and was formulated to describe the behavior of a perfect gas. Look at the following equation:
P.V = n.R.T
P = pressure generated by the gas on the walls of the container;
V = volume occupied by the gas and can be expressed in liters or cubic meters;
n = number of mol (amount of substance in the gas);
Obs.: The number of moles is expressed by the ratio between the mass of the gas (m) and its molar mass (M);
R = general gas constant proposed by Clapeyron and depends on the pressure unit used (in atm, it is 0.082; in mmHg, it is 62.3; in KPa, it is 8.31);
T = temperature at which the gas is subjected (always used in the unit Kelvin).
The question gives us:
V = 20 L
P = 13 atm
T = 278
R = 0.082
So:
13*20 = n*0.082*278
n = 260/22.796
n = 11.4 moles
Answer:n = 11.4 moles