Lesson 6: What are chemical rates?

What Are Chemical Kinetics?

Have you ever wondered why explosions happen very quickly? Or why if you leave your bike in the rain it rusts so slowly you can’t even see it happening? And how do scientists know how old ancient manuscripts or prehistoric skeletons are anyway?

These are all questions of chemical kinetics. Chemists can measure how much of a reacting chemical is present over time. Take a look at the information in the file carbon_data.cvs. Notice how the amount of Carbon-14 in the sample is decaying over time.

What is happening here? When scientists talk about carbon dating, they are referring to a specific reaction. This reaction is the nuclear decay of an unstable species of carbon, called carbon-14 because it has a total of 14 protons and neutrons in its nucleus. Each year a little bit of carbon-14 decays, converting a neutron into a proton, giving off a beta particle, and leaving behind a nitrogen atom. When an plant or animal is alive it replaces the carbon-14 from the carbon dioxide it photosynthesizes or the food it eats respectively, but once it dies it begins to slowly lose its carbon 14.