Question

In van der Waals equation at constant temperature 300 K, if a = 1.4 atm L mol, V = 100 mL, n = 1 mole, then what is the pressure of the gas?

• A. 42 atm
• B. 210 atm
• C. 500 atm
• D. 106 atm

Answer 1

Answer: (D)

106 atm

Answer 2

At moderate pressure van der Waals equation is given as : $\left(P+\frac{an^{2}}{V^{2}}\right)\left(V\right)=nRT$ $\left(P+\frac{1.4}{\left(0.1\right)^{2}}\right)\left(0.1\right)=1\times0.082\times300$ $\left(P + 140\right) ??0.1 = 24.6$ $0.1 P + 14 = 24.6$ $0.1 P = 10.6 \Rightarrow P = 106$ atm