Today in Science History – January 14 – Cato Guldberg and the Law of Mass Action

Guldberg and Waage
Cato Guldberg and Peter Waage discovered the Law of Mass Action relating the rate of a reaction to the concentrations of the reactants.

January 14 marks the passing of Cato Guldberg. Guldberg was a Norwegian chemist and mathematician who, with his brother-in-law, Peter Waage discovered the chemistry law of mass action.

The law of mass action relates the rate a chemical reaction progresses to the concentrations of the reactants. Up to this point, the rate of a reaction was thought to depend on the chemical affinity between the two reactants. For the reaction aA + bB → C, the reaction rate would be proportional to the concentrations of A and B and their stoichiometric ratios a and b. The proportionality constant between them is known as the rate constant, k.

reaction rate = k[A]a[B]b

When you think about it, a reaction is more likely to proceed quickly when there is more stuff to do the reaction.

The two weren’t immediately recognized for their discovery. The path to recognition involved a lesson in publishing in the language of who you want to gain recognition from. They published their new findings in a Norwegian scientific journal and consequently, the rest of the chemical world basically never heard of the work. The scientific community doesn’t often follow Norwegian journals. They republished their work in a French journal and the work remained obscure until German chemist, Wilhelm Ostwald published an article that mentioned the law and proved it with experiments of his own. When Dutch chemist Jacobus van’t Hoff derived his kinetics equations in 1888 and received credit for ‘discovering’ the relationship, they republished their original work in German. This time, they were recognized for being the original discoverers of mass action. German and English were the languages of chemistry in the 19th Century.

Another relationship Guldberg is known for came about from his investigations into how dissolved substances affect the freezing point and vapor pressure of the pure liquid. Guldberg discovered a relationship between boiling point and critical point of a liquid. The boiling point is the temperature where the vapor pressure of a liquid equal to the pressure surrounding the liquid and the liquid becomes a gas. The critical point is the temperature where there are no longer any phase boundaries. Guldberg showed the temperature of the boiling point is two-thirds the temperature of the critical point when measured on the absolute temperature scale. This relationship is known as Guldberg’s Rule.

Other Notable Science Events for January 14

2005 – Huygens probe lands on Titan.

Huygens Probe
Artist’s impression of Huygens probe sitting on Titan.

The European Space Agency’s Huygens probe touched down on the surface of Saturn’s moon, Titan. It was part of the Cassini-Huygens spacecraft mission to Saturn. The probe detached from the main spacecraft and landed two weeks later. The probe sent back images and data for another 90 minutes before battery power was drained.

The probe was named for Dutch astronomer Christiaan Huygens who discovered the rings of Saturn and the moon, Titan.

1934 – Paul Vieille died.

Paul Vieille (1854 - 1934)
Paul Vieille (1854 – 1934)

Vieille was a French chemist who successfully created the first smokeless gunpowder. Nitrocellulose was found to be an effective alternative to gunpowder in the form of gun cotton. The problem was gun cotton was a highly unstable material and a danger to everyone involved in its manufacture and use. Vieille discovered a method to suspend nitrocellulose as a colloid into a variety of solvents that could be pressed into a useful and stable form.

1902 – Cato Maximilian Guldberg died.

1742 – Edmond Halley died.

Edmond Halley
Edmond Halley (1656 – 1742)

Halley was an English natural philosopher who was the second Astronomer Royal.

Halley is best known for calculating the orbit of the comet that bears his name. He calculated the comets observed in 1456, 1531, 1607, and 1682 were all the same comet. He added this comet would return in 1758. Unfortunately for him, he did not live to see his prediction come true.

Halley also began a catalogue of Southern Hemisphere stars to accompany his predecessor John Flamsteed’s Northern Hemisphere star catalogue.  He gathered data on 341 stars before being recalled to England.

He was also was the publisher and editor of Isaac Newton’s Principia Mathematica Philosophiae Naturalis.