Water standing in the open at 28.4°C evaporates because of the escape of some of the surface molecules. The heat of vaporization (542 cal/g) is approximately equal to ɛn, where ɛ is the average energy of the escaping molecules and n is the number of molecules per gram. (a) Find ɛ. (b) What is the ratio of ɛ to the average kinetic energy of H2O molecules, assuming the latter is related to temperature in the same way as it is for gases?

Water standing in the open at 28.4°C evaporates because of the escape of some of the surface molecules. The heat of vaporization (542 cal/g) is approximately equal to ɛn, where ɛ is the average energy of the escaping molecules and n is the number of molecules per gram. (a) Find ɛ. (b) What is the ratio of ɛ to the average kinetic energy of H2O molecules, assuming the latter is related to temperature in the same way as it is for gases?

College Physics

11th Edition

ISBN:9781305952300

Author:Raymond A. Serway, Chris Vuille

Publisher:Raymond A. Serway, Chris Vuille

Chapter1: Units, Trigonometry. And Vectors

Section: Chapter Questions

Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...

See similar textbooks

Similar questions

The pressure unit 1 torr is comparable to 0.001 bar. In a sample of N₂ at this pressure and a temperature of 300 K, what is the mean free path between collisions in mm (millimeters)? Assume that the cross-section for N₂ molecules is o = 4.50 × 10-19 m².
Consider the thermodynamic process, A->B->C->A shown above. The heat absorbed during A->B is 591J. If the change in internal energy during B->C is 4146J, What is the change in internal energy in SI units during C->A? Express only the number of your answer with 4 significant figures.
Please do correctly.
On a hot summer day, the density of air at atmospheric pressure at 35 °C is 1.1455 kg/m3. What is the number of moles contained in 1 m3 of ideal gas at this temperature and pressure? Avogadro’s number of air molecules has a mass of 2.85×10-2kg. what is the mass of 1 m3 of air? Does the value calculated in part (B) agree with the stated density of air at this temperature?
Problem 2: The enthalpy of a system is given by the equation H = U + PV where U is the internal energy, P = pressure, and V = volume. In addition, the internal energy, U = Q + W where Q is the heat and W is the work. Suppose we want to find the rate of change in the enthalpy at constant pressure of 1.25 atm, what is the value when heat is absorbed by the system at a rate of 45 J/s and work is done by the system at a rate of 100 J/s when the change of volume is rated at 35 x 105 m/s? 1. What is the change in heat with respect to time? 2. What is the change in internal energy of the system with respect to time? 3. What is the change in enthalpy of the system with respect to time?
How long would it take a persons with an average body (surface area of 1.8 m^2 and normal body temperature of 37◦C) to heat up a room (which hold 2700 moles of air) from 16.370◦C to 16.373◦C?
The pressure, volume, and temperature of a mole of an ideal gas are related by the equation PV = 8.31T, where P is measured in kilopascals, V in liters, and T in kelvins. Use differentials to find the approximate change in the pressure if the volume increases from 10 L to 10.6 L and the temperature decreases from 335 K to 330 K. (Note whether the change is positive or negative in your answer. I Round your answer to ti decimal places.
Suppose that the root-mean-square velocity vms of water molecules (molecular mass is equal to 18.0 g/mol) in a flame is found to be 1350 m/s. What temperature T does this represent? The Boltzmann constant is k = 1.38 x 10-23 J/K and Avogadro's number is NA = 6.022 x 1023 mol-'. T = K
A container is filled with an ideal diatomic gas to a pressure and volume of P1 and V1, respectively. The gas is then warmed in a two-step process that increases the pressure by a factor of five and the volume by a factor of four. Determine the amount of energy transferred to the gas by heat if the first step is carried out at constant volume and the second step at constant pressure. (Use any variable or symbol stated above as necessary.)
A flask made of Pyrex is calibrated at 20.0°C. It is filled to the 100-mL mark on the flask with 35.0°C acetone. (a) What is the volume of the acetone when both it and the flask cool to 20.0°C? (b) Would the temporary increase in the Pyrex flask’s volume make an appreciable difference in the answer? Why or why not?
The heat equation in 1D is : du = Ở o = constant (a) Given that [t] = T and [x] = L, what is the dimension of o ? Infer a dimensionless variable z A x tª oß.
The gas constant R has the value 287 J/Kg * K for dry air. Using the ideal gas law (P = PanyRT): a) Find the density of dry air at 72.05 "F with a pressure of 1095 mb. b.) Find the density of molst air at the same pressure and temperature if the relative humidity is 60%. HINT: (for o) stick with Si units (for b) Find e, given T(see lecture slides). Find e given RH. Find pos from: P 0.378e 0.378e Pmoist 1 or Pmoist = Pary RT P