An elimination reaction is a type of organic reaction in which two substituents are removed from a molecule in either a one or two-step mechanism. The one-step mechanism is known as the E2 reaction, and the two-step mechanism is known as the E1 reaction. The numbers do not have to do with the number of steps in the mechanism, but rather the kinetics of the reaction, bimolecular and unimolecular respectively.

In most organic elimination reactions, hydrogens are lost to form the double bond: the unsaturation of the molecule increases. It is also possible that a molecule undergoes reductive elimination, by which the valence of an atom in the molecule decreases by two. An important class of elimination reactions are those involving alkyl halides, with good leaving groups, reacting with a Lewis base to form an alkene. Elimination may be considered the reverse of an addition reaction. When the substrate is asymmetric, regioselectivity is determined by Zaitsev's rule.

During the 1920s, Sir Christopher Ingold proposed a model to explain a peculiar type of chemical reaction; the E2 mechanism. E2 stands for bimolecular elimination.

Judith Hill is an American singer born in Los Angeles, California.

Hill's mother is a pianist from Tokyo who met Hill's father in a funk band in the 1970s. Together they raised Judith in a very musical household. She is of both Japanese and Black descent.

After getting a degree in music composition from Biola University in southern California, Hill went to France in 2007 to perform with the French singer Michel Polnareff. She began a career as a singer-songwriter when she returned to the United States. In 2009, she was selected as one of Michael Jackson's back-up singers for his planned comeback This Is It concerts.

Michael Jackson's death on June 25, 2009, caused the tour to be cancelled. Along with the rest of the This Is It cast members, she performed at Jackson's memorial service at the Staples Center in downtown Los Angeles on July 7, 2009. She attracted global attention when she sang the lead on the song "Heal the World", which was one of the climactic moments of the service. Approximately one billion people worldwide are believed to have viewed her performance.