Report of Investigations 7691: Low-Temperature Heat Capacities and High-Temperature Enthalpies of Sodium Chromate

Details

• Personal Author:
  Ferrante, Michael J. ; Krug, Marion P. ; Stuve, John M.
• Corporate Authors:
  United States. Bureau of Mines
• Description:
  Low-temperature heat capacities and high-temperature enthalpies were determined calorimetrically for na2cro4. A reversible transition was found at 700 deg k with an isothermal heat of transition of 2,263 cal/mole. High-temperature x-ray diffraction analysis showed that the transition was a crystal change from the low-temperature orthorhombic form to the high-temperature hexagonal form. At 795 deg k the hexagonal form had the parameters ao = 5.691 and CO = 7.478 A. Powder diffraction data for the high-temperature form are given and possible structures discussed. The melting point was determined to be 1,065 deg k with a heat of fusion of 5,810 cal/mole. Enthalpy and entropy increments from this investigation were combined with other data from the literature to calculate enthalpies of formation, free energies of formation, and equilibrium constants for formation from 298 deg to 1,400 deg k. Equations that represent enthalpies above 298 deg k are given. Work done under an agreement with the U.S. Atomic Energy Commission. [Description provided by NIOSH]
• Subjects:
  Chemistry Occupational Health Safety
• Series:
  Mining Publications
• Subseries:
  Report of Investigations
• ISSN:
  1066-5552 (print)
• Publisher:
  United States. Bureau of Mines
• Document Type:
  Text
• Genre:
  Case Report
• Rights:
  Public Domain
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  ALRC - Albany Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  18 pdf pages
• NIOSHTIC Number:
  nn:10008943
• NTIS Accession Number:
  PB-213876
• Citation:
  NTIS: PB 213 876 :12 pages
• Federal Fiscal Year:
  1972
• Peer Reviewed:
  False
• Source Full Name:
  NTIS: PB 213 876
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:f05ccdd8b2ceb9bf1545e927cfc799e482f96fd1e78e75419f6b94bcffcd251ff764dedde355247c04a287217b0b180fa728587c34628457c8fb7348ffcf762a
• Download URL:
  https://stacks.cdc.gov/view/cdc/201941/cdc_201941_DS1.pdf
• File Type:
  [PDF - 597.24 KB ]