Question

In a closed container, the vapor pressure of 10 mL of ethanol at 20 degrees C is 5.85 kPa. What is the vapor pressure of 20 mL of ethanol at the same temperature?

Answer 1

Answer:

${P_2}=2.925\ kPa$

Explanation:

At same temperature and same number of moles, Using Boyle's law  

${P_1}\times {V_1}={P_2}\times {V_2}$

Given ,  

V₁ = 10 mL

V₂ = 20 mL

P₁ = 5.85 kPa

P₂ = ?

Using above equation as:

${P_1}\times {V_1}={P_2}\times {V_2}$

${5.85\ kPa}\times {10\ mL}={P_2}\times {20\ mL}$

${P_2}=\frac{{5.85}\times {10}}{20}\ kPa$

${P_2}=2.925\ kPa$