Please Help Me! I can't figure out why pressure comes out to be 18.77 every time. The graph only graphs volume and pressure at 18.77 atm

Using Matlab, calculate the pressure (P) (in atm) of a gas in a container of volume (V) ( in liters) for concentrations of 1 ≤ n ≤ 6 at T = 300 K and for volumes of 0.08 ≤ V ≤ 8 liters, where R = 0.08206 Latm/molK, a = 1.39 L2 atm/mol2, and b = 0.0391 L/mol.

(a) Plot P vs. V for all concentration in one plot using different colors for each concentration. Make sure your axes are properly labeled, including units.

(b) Generate a composite plot of P vs. V in which each concentration is represented by a subplot.

%van derWaals equation: %P = [(n*R*T)/(V-n*b)]-[(n^2*a)/(V^2)] %T = 300K %R = 0.08206 (L*atm)/(mol*K) %a = 1.39 (L^2*atm)/(mol^2) %b = 0.0391 L/mol %Calculate the pressure (atm) of a gas in a container of volume (V)(liters) %For concentrations of 1 <= n <= 6 %For volumes of 0.08 <= V <= 8

%Create a function

function [ P ] = Pressure_AbuHamdeh( ~ )

%Declare variables

R = 0.08206;

T = 300;

a = 1.39;

b = 0.0391;

%For concentrations of 1 <= n <= 6

n = 1:6;

%For volumes of 0.08 <= V <= 8

V = linspace(0.8,8,6);

%van DerWaals equation

P = (n.*R*T)/(V-n.*b) - (n.^2*a)/(V.^2);

plot(V,P,'-p');

xlabel('Volume (Liters)') ylabel('Pressure (atm)') title('Graph of Pressure vs Volume')

end

Answer 1

[James Tursa]

Elementwise division also. E.g.,

P = (n.*R*T)./(V-n.*b) - (n.^2*a)./(V.^2);