QUESTION IMAGE
Question
liquid a is known to have a higher viscosity and higher vapor pressure than liquid b. use these facts to predict the result of each experiment in the table below, if you can.
| experiment | predicted outcome |
|---|---|
| 15.0 ml of liquid a are poured into a beaker. 15.0 ml of liquid b are poured into another beaker. after 90 minutes have passed, the volumes $v_a$ and $v_b$ of liquid in each beaker are measured. | $v_a$ will be greater than $v_b$ <br> $v_a$ will be less than $v_b$ <br> $v_a$ will be equal to $v_b$ <br> its impossible to predict whether $v_a$ or $v_b$ will be greater without more information. |
Experiment 1:
Step1: Viscosity and flow - pressure relationship
Viscosity (\(\eta\)) is related to the pressure (\(P\)) needed to maintain a flow rate (\(Q\)) through a tube of radius \(r\) and length \(L\) by the Hagen - Poiseuille equation \(Q=\frac{\pi r^{4}P}{8\eta L}\). For a given \(Q\), \(r\), and \(L\), \(P = \frac{8\eta LQ}{\pi r^{4}}\). Since Liquid A has a higher viscosity (\(\eta_A>\eta_B\)), and other factors (\(Q\), \(r\), \(L\)) are the same (same tube diameter means same \(r\), same flow rate \(Q\)), the pressure \(P\) is directly proportional to viscosity.
Step2: Compare \(P_A\) and \(P_B\)
From \(P = \frac{8\eta LQ}{\pi r^{4}}\), when \(\eta_A>\eta_B\), \(P_A\) (pressure for Liquid A) will be greater than \(P_B\) (pressure for Liquid B).
Experiment 2:
Step1: Vapor pressure and evaporation
Vapor pressure (\(P_{vap}\)) is a measure of the tendency of a liquid to evaporate. A liquid with a higher vapor pressure evaporates more readily. Liquid A has a higher vapor pressure (\(P_{vap,A}>P_{vap,B}\)).
Step2: Compare \(V_A\) and \(V_B\)
The initial volumes (\(V_{0,A} = V_{0,B}=15.0\space mL\)) are the same. After 90 minutes, the volume of the liquid remaining \(V = V_0 - \Delta V\), where \(\Delta V\) is the volume of liquid that has evaporated. Since \(P_{vap,A}>P_{vap,B}\), Liquid A evaporates more (\(\Delta V_A>\Delta V_B\)), so \(V_A=V_{0,A}-\Delta V_A\) and \(V_B = V_{0,B}-\Delta V_B\), and \(V_A\) will be less than \(V_B\).
Snap & solve any problem in the app
Get step-by-step solutions on Sovi AI
Photo-based solutions with guided steps
Explore more problems and detailed explanations
- For the first experiment: \(P_A\) will be greater than \(P_B\)
- For the second experiment: \(V_A\) will be less than \(V_B\)