This tumblr's for all the great men and women of science for whom we owe our current understanding of the natural world; their achievements, their failures, and even their quirks, we celebrate them all.
For Science. For Inquiry. For Humanity.
Single Replacement Reaction
A single replacement reaction occurs when two different cations switch places to combine with the same anion. One element forms a compound while another element is released from the compound.
In a single replacement reaction, or single displacement reaction, a single uncombined element replaces another in a compound. Two reactants yield two products. For example when zinc combines with hydrochloric acid, the zinc replaces hydrogen.
Cu (s) + AgNO3 (aq) → Ag(s) + Cu(NO3)2 (aq)
A common way of drawing out the structure of molecules (esp. in organic chemistry) is to use a skeletal formula.
In a skeletal formula, a C-C bond is symbolized by a straight line. A C-C-C chain would be a straight line with another straight line coming off the first at an angle (to distinguish the bonds). C-H bonds are not shown in skeletal formulae. Instead, you are assumed to know which Carbon atoms should have C-H bonds and how many they should have.
Any atoms that are not C or H are called heteroatoms, and their element symbols must be explicitly written into the structure (as well as any bonds between heteroatoms and hydrogen atoms)
A human brain preserved in a jar of formaldehyde (CH2O). Formaldehyde is a crosslinking fixative and acts by creating covalent bonds between proteins in tissue. This anchors soluble proteins to the cytoskeleton, and lends additional rigidity to the tissue. Additionally, it acts as a disinfectant, killing most types of bacteria and fungi.
“We never can tell how our lives may work to the account of the general good, and we are not wise enough to know if we have fulfilled our mission or not.”—Ellen Swallow Richards
Born this day in 1842: Ellen Swallow Richards (1842–1911), first woman to study science at MIT, promoter of science education for women, and pioneer in the fields of urban and industrial sanitation, food safety, water purity, ecology, and many other environmental sciences.
Phenylthiocarbamide (PTC) (AKA phenylthiourea (PTU))
PTC is a molecule that looks like .
The story of this molecule is as follows. One day, Arthur Fox was using some PTC powder and accidentally made a mistake, leading it to disperse in the room. A colleague complained about the bitter taste of the molecule while Fox tasted nothing.
This led to him testing this bitter taste on family and friends, and found a strong familial (therefore genetic) correlation. At this time, DNA tests were not developed yet, and PTC taste tests were used as paternity tests.
In 2003, the PTC gene (TAS2R38) was discovered, and the ability to taste the bitterness is a dominant (or incomplete dominant) allele. People have been noted to taste different degrees of bitterness, to some believe it is incomplete dominance.
Under EU classification, PTC is very toxic.
PTC is also said to inhibit melanogenesis and is used to grow transparent fish.
PTC paper can be used to test, but because of its toxicity, should only be tested once.
Monkeys apparently have a similar trait, but the gene regulating it it different.
Marie-Anne Lavoisier (nee. Paulze, 1758 – 1836), was a French chemist. She was born in the town of Montbrison, Loire, in a small province in France. She was the wife of Antoine Lavoisier and acted as his laboratory assistant and contributed to his work.
When Marie-Anne was 13, her mother died and she was place in a convent where she received her formal education. At this time she also received a marriage proposal from someone who was nearly three times her age. Her father tried to thwart the marriage and ended up having one of his colleagues offer a proposal. This man was Antoine Lavoisier, a French noblemen and scientist. They were married in 1771, when he was 28 and Marie-Anne was 13.
Antoine was appointed gunpowder administrator and had a chemistry laboratory. Marie-Anne soon became interested in her husband’s scientific research and began to participate in his research. The Lavoisiers spent most of their time together in the laboratory, working as a team conducting research on many fronts. She also assisted him by translating documents about chemistry from English to French. In fact, the majority of the research effort put forth in the laboratory was actually a joint effort between Marie-Anne and her husband, with her mainly playing the role of laboratory assistant.
Marie-Anne made many contributions to her husband’s research and the field of chemistry by keeping detailed lab notebooks, accurately drawing experimental apparatuses so others could understand the methods, and translating and editing his reports. Perhaps her most important translation was that of Richard Kirwan’s essay ‘Essay on Phlogiston and the Constitution of Acids’, which she both translated and critiqued. Marie-Anne also contributed to Lavoisier’s ‘Elementary Treatise on Chemistry’ (1789), which presented a unified view of chemistry as a field. She contributed thirteen drawings that showed all the laboratory instrumentation and equipment used by the Lavoisiers in their experiments.
In 1794, Antoine was imprisoned and later executed during the Reign of Terror. Marie-Anne eventually remarried to a physicist but the marriage was short-lived. She died in 1836 at the age of 78.
Friends are like gold.
They dissolve in hydrochloric acid mixed with nitric acid (3:1)