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Catalyst

KAT-uh-list /ˈkætəlɪst/

nounC1GRESATTOEFL

formaltechnical

A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

Catalysts are crucial in both industrial processes and biological systems (where they are called enzymes). They lower the activation energy of a reaction.

The story behind the word. The word 'catalyst' comes from the Greek 'katalysis,' meaning 'dissolution' or 'unloosing.' It's formed from 'kata-' (meaning 'down' or 'completely') and 'lyein' (meaning 'to loosen' or 'to dissolve'). Jöns Jacob Berzelius, the same chemist who coined 'polymer,' introduced the term in 1835 to describe substances that 'loosen' or facilitate chemical reactions without being consumed themselves.

Word relationships

accelerator: More general term for something that speeds up a process.
initiator: Starts a process, but doesn't necessarily speed it up without being consumed.
stimulus: Something that causes a reaction or change, but not necessarily a chemical one.

inhibitor: A substance that slows down or prevents a chemical reaction.

Commonly confused with

Reactant: A reactant is consumed in a chemical reaction; a catalyst is not.

Word family

catalyze (verb): to cause or accelerate (a reaction) as a catalyst
catalytic (adjective): relating to or involving catalysis
catalysis (noun): the acceleration of a chemical reaction by a catalyst

Collocations

chemical catalyst
biological catalyst
industrial catalyst
catalyst bed
catalyst poisoning

Idioms & expressions

a catalyst for change

Example sentences

"The enzyme acted as a catalyst, speeding up the digestion of complex carbohydrates." Enzymes are biological catalysts that accelerate biochemical reactions in living cells.
"The new catalyst allowed the chemical plant to synthesize the polymer at a lower temperature and pressure." In industrial chemistry, catalysts are essential for efficient and cost-effective production.
"The invention of the printing press was a powerful catalyst for the spread of knowledge." His inspiring speech served as a catalyst for social change.

Memory hook

Think 'CAT-apult' (launches something) and 'CAT-alyst' (launches or speeds up a reaction). Speeds reaction, unchanged.

When not to use

Do not use 'catalyst' for a substance that is consumed in the reaction or for something that merely initiates a process without accelerating it (e.g., a spark is not a catalyst for combustion).

Fun facts

Many industrial processes, such as the Haber-Bosch process for ammonia synthesis, would be economically unfeasible without efficient catalysts.
The catalytic converter in cars uses precious metals like platinum, palladium, and rhodium as catalysts to convert harmful pollutants into less toxic substances.