What is the equilibrium constant?

Imagine a bathtub that someone forgot to plug, but they left the tap open. If the water from the tap is running fast enough, after some time the speed at which water drains and the speed at which water fills the bathtub will equalibrate, and the water level inside the bathtub will remain constant. Although the system is constantly changing ('new' water flowing in and 'old' water draining), you can't notice it as the apparent level of water remains the same. It is the same with chemical reactions. Imagine a reversible chemical reaction: A <-> B The speed at which A gets converted to B would be v(forward)=k(forward)[A] At the same time, we lose some product because it gets converted back to A. The speed at which B gets converted to B would be v(reverse)=k(reverse)[B] In equalibrium, the two rates are the same. Therefore we can say: v(forward)=v(reverse) k(forward)[A]=k(reverse)[B] k(forward)/k(reverse)=[B]/[A], which is the equilibrium constant, K. It is useful for many chemical calculations, and a general definition is: for a reaction a A + b B -> c C + d D, the equilibrium constant K=([C]^c*[D]^d)/([A]^a*[B]^b).

WL
Answered by Wojciech L. Chemistry tutor

2476 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

Why do certain metals give off different colours when heated?


An unknown gas from a reaction is contained in a 2 litre beaker, at standard atmospheric pressure and a Temperature of 25 Celsius. Calculate the number of moles of the gas.


Why does ionisation energy decrease down group 2?


Which compound has a higher boiling point and why: water (H2O) or methane (CH4)?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2025

Terms & Conditions|Privacy Policy
Cookie Preferences