Accession Number:

AD0010066

Title:

HEAT CAPACITY OF AMMONIUM CHROMIUM ALUM

Descriptive Note:

Corporate Author:

OHIO STATE UNIV RESEARCH FOUNDATION COLUMBUS CRYOGENIC LAB

Personal Author(s):

• JOHNSTON, HERRICK L.
• HU, JIH-HING
• HORTON, WILLIAM S.

Report Date:

1953-04-20

Pagination or Media Count:

21.0

Abstract:

The heat capacity of 2 samples of NH4CrSO42 12H2O was measured from 18 to 305 K. A second-order transition was found in the region between 92 and 97 K with a heat and entropy of transition equal to 267.4 or - 0.1 cal and 2.83 or - 0.1 EU, respectively. The transition tended to disappear under supercooling conditions. The results are compared with the observations of Kraus and Nutting J. Chem. Phys. 9 133, 1941. The samples which showed transitions became opaque after a few minutes in the N or H cooling liquid, as though they were broken into an infinite number of tiny crystals by the disruption of the lattice. The production of the multicrystalline material was attributed to a volume change under hysteresis conditions.

Descriptors:

• *SPECIFIC HEAT
• PRODUCTION
• LIQUIDS
• CRYSTALS
• ENTROPY
• HYSTERESIS
• SUPERCOOLING
• VOLUME
• COOLING

Subject Categories:

• Thermodynamics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE