Concept explainers
Knudsen effusion cells are used to determine vapor pressures of high-temperature materials. For example, a Knudsen cell is filled with tungsten and heated to
Want to see the full answer?
Check out a sample textbook solutionChapter 19 Solutions
Student Solutions Manual for Ball's Physical Chemistry, 2nd
- The vapor pressure of liquid carbon tetrachloride, CC14, is 15, 539 Pa at 290 K and 69,518 Pa at 340 K. The vapor pressure of solid carbon tetrachloride is 275 Pa at 232 K and 2,092 Pa at 250 K. Estimate the temperature of the triple point of carbon tetra- chloride.arrow_forwardThe standard enthalpy of vaporization of water, H2O, ΔvapH = 40.7 kJ/mol at 373 K. Assuming this value to remain constant at temperatures close to 373 K, use the Clausius-Clapeyron equation to estimate the vapor pressure of liquid water at 80°C.arrow_forwardPrior to the discovery that freon-12 (CF2Cl2) is harmful to the Earth’s ozone layer it was frequently used as the dispersing agent in spray cans for hair spray etc. Estimate the pressure that a can of hair spray using freon-12 has to withstand at 40 °C, the temperature of a can that has been standing in sunlight. The enthalpy of vaporization of freon-12 at its normal boiling point of −29.2 °C is 20.25 kJ mol−1; assume that this value remains constant over the temperature range of interest.arrow_forward
- (b) Using the Crystallographer's formula to determine the density (in g/cm³) of Po: ρ = Σ Ζ * Μ Vell* N You must know that a primitive cubic cell has Z = 1 Since Po is a metal, the value of "i" = 1, since it's the only entity! MM of Po= 208.998 g/mol Vcell (in cm³) = a³ Vcell (3.36 x 10-8 cm)³ = 3.793 x 10-23 cm³ N = 6.022 x 1023 atoms/mol Thus: p = (1 atom/cell) (208.998 g/mol) = 9.16 g/cm³ (3.793 x 10-23 cm³) (6.022 x 1023)arrow_forwardAt room temperature, monoclinic sulfur has the unit-cell dimensions a = 11.04 Å, b = 10.98 Å, c = 10.92 Å, and B = 96.73°. Each cell contains 48 atoms of sulfur. (a) Explain why it is not necessary to give the values of the angles a and y in this cell. (b) Compute the density of monoclinic sulfur (in g cm¯³).arrow_forwardFor liquid zinc, the measured vapour pressures at 627 °C and 977 °C are given as 9.5 x 10-3 atm and 0.116 atm,respectively. Using the derived equation to calculate the boiling temperature (TB,Zn) and enthalpy of boiling for zinc (∆HB,Zn).arrow_forward
- In the early days of X-ray crystallography there was an urgent need to know the wavelengths of X-rays. One technique was to measure the diffraction angle from a mechanically ruled grating. Another method was to estimate the separation of lattice planes from the measured density of a crystal. The mass density of NaCl is 2.17 g cm−3 and the (100) reflection using radiation of a certain wavelength occurred at 6.0°. Calculate the wavelength of the X-rays.arrow_forwardImage shows a part of the phase diagram of an alloy of copper and aluminium. Describe what would be observed as a melt of composition a is cooled. What is the solubility of copper in aluminium at 500 °C?arrow_forwardThe vapor pressure of benzene is 224 mmHg at 45 °C and 648 mmHg at 75 °C.(a) Find the enthalpy of vaporization of benzene, ∆Hvap (kJ/mol), assuming it is constant. You may also assume that ZV − ZL ≃ 1. B)arrow_forward
- The molar enthalpy of vaporization of water is Avap H = 40.65 kJ molat its normal boiling point. Use the Clausius-Clapeyron equation (given below) to calculate the vapor pressure of water at 105.96 °C. Assume Avan H does not depend on temperature. Give your answer in torr with at least one decimal place. dIn P dT RTarrow_forwardA liquid has a vapor pressure of 32.8 kPa at 26.4 °C. Its vapor pressure at 96.5 °C is 75.4 kPa. What is the enthalpy of vaporization (AHvap) for the liquid in kJ?arrow_forward(a) Temperature dependence of the vapor pressure of ethylene log p (mm Hg) = - 834.13 / T + 1.75 log T - 8.375 x 10-3 T + 5.3234 , which gives the temperature dependence of the molar enthalpy of vaporization derive the equation. (b) Calculate the molar enthalpy of evaporation at -103.9 oC, the normal boiling point of ethylene. Note: Use the equation that gives the temperature dependence of ΔHvap= a + bT + cT2+ ….enthalpy.arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY