Kopp's law explained

Kopp's law can refer to either of two relationships discovered by the German chemist Hermann Franz Moritz Kopp (1817–1892).

1. Kopp found "that the molecular heat capacity of a solid compound is the sum of the atomic heat capacities of the elements composing it; the elements having atomic heat capacities lower than those required by the Dulong–Petit law retain these lower values in their compounds."^[1]
2. In studying organic compounds, Kopp found a regular relationship between boiling points and the number of CH₂ groups present.^[2]

Kopp–Neumann law

The Kopp–Neumann law, named for Kopp and Franz Ernst Neumann, is a common approach for determining the specific heat C (in J·kg⁻¹·K⁻¹) of compounds using the following equation:^[3] $$C\; =\; \backslash sum\_^N\; C\_i\; f\_i,$$ where N is the total number of compound constituents, and C_i and f_i denote the specific heat and mass fraction of the i-th constituent. This law works surprisingly well at room-temperature conditions, but poorly at elevated temperatures.

See also

• Rule of mixtures

References

• Frederick Seitz, The Modern Theory of Solids, McGraw-Hill, New York, USA, 1940, ASIN: B000OLCK08

1. See page 96 of Book: Physical Chemistry for Colleges . Millard, Earl Bowman . 1921 . McGraw-Hill. New York . 96 . Kopp's Law. .
2. See page 942 of Book: Elements of Chemistry . Miller, William Allen . 1869. Longmans, Green, Reader, and Dyer . London .
3. Kauwe. Steven K. . Graser. Jake . Vazquez. Antonio . Sparks. Taylor D. . 2018-05-29. Machine Learning Prediction of Heat Capacity for Solid Inorganics. Integrating Materials and Manufacturing Innovation. 7 . 2 . 43–51 . 10.1007/s40192-018-0108-9 . 65239690 . 2193-9764 . free.

Further reading

• The Life Work of Hermann Kopp . Thorpe, T. E. . Memorial Lectures Delivered Before the Chemical Society . 1901 . 25 . 774 - 815 .