• Chemical reactions: Some are super quick, like explosions (think of fireworks!), and others are ultra-slow, like making fossil fuels (imagine waiting a few million years for your car's fuel!).
• “Fast” and “Slow”? Too vague for science! So, let’s get precise.

• It's like measuring how fast you run, but for chemicals!
• Rate of Reaction (ν) = Change in concentration (Δc) / Time taken (Δt)
• Fancy term: This is the average rate. Like your average speed during a jog.
• Units? Usually: moldm⁻³ s⁻¹. But there are others like mmoldm⁻³min⁻¹.

It's always positive! Just like you can't run at a -5 km/hr speed. We use the absolute value (that vertical line thing - |Δc|) to ensure this.

If species X's concentration drops from 0.50 to 0.20 in 25 seconds, it's like dropping 30 cents in 25 seconds. The rate? 0.012 moldm⁻³ s⁻¹.

• In a reaction, if molecules are not reacting in a 1:1 ratio, their individual reaction rates vary.
• Fun fact: We can adjust for this! Just divide by their stoichiometric coefficients.