- Scottish physicist
and chemist who in 1754 discovered carbon dioxide (which he called
'fixed air'). By his investigations in 1761 of latent heat and specific
heat, he laid the foundation for the work of his pupil
James Watt.
In 1756 Black described how carbonates become more alkaline when they
lose carbon dioxide, whereas the taking-up of carbon dioxide reconverts
them. He discovered that carbon dioxide behaves like an acid, is produced
by fermentation, respiration, and the combustion of carbon, and guessed
that it is present in the atmosphere. He also discovered the bicarbonates
(hydrogen carbonates).
Born in Bordeaux, France, Black qualified as a doctor in Edinburgh,
where he became professor of chemistry.
Black noticed that when ice melts it absorbs heat from its surroundings
without itself undergoing a change in temperature, from which he argued
that the heat must have combined with the ice particles and become
latent. He also observed that equal masses of different substances
require different quantities of heat to change their temperatures
by the same amount, an observation that established the concept of
specific heat capacity.
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