ALK or Alk may refer to:
In organic chemistry, an alkane, or paraffin (a historical name that also has other meanings), is an acyclic saturated hydrocarbon.
The alkali metals are a group (column) in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr).
The alkaline earth metals are six chemical elements in column (group) 2 of the Periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
In organic chemistry, an alkene is an unsaturated hydrocarbon that contains at least one carbon–carbon double bond.
Alkaloids are a group of naturally occurring chemical compounds that mostly contain basic nitrogen atoms.
Alkaline phosphatase (ALP, ALKP, ALPase, Alk Phos) (EC 220.127.116.11) is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides, proteins, and alkaloids.
Alkaline Trio is an American punk rock band from McHenry, Illinois. The band consists of guitarist and vocalist Matt Skiba, bassist and vocalist Dan Andriano, and drummer Derek Grant.
Alka Yagnik is an Indian playback singer. She is noted in Hindi cinema for a career spanning over three decades.
Alkalinity is the name given to the quantitative capacity of an aqueous solution to neutralize an acid.