Rate of Reaction Fundamentals
Rate of reaction measures how quickly reactants turn into products over time. You can think of it as either the gain of products or the loss of reactants as time passes. When you plot this on a graph, fast reactions show up as steep curves that quickly level off, whilst slow reactions have gentler slopes.
The graph always starts steep and then flattens out when the reaction finishes. This happens because you run out of reactants - there's nothing left to react! A steeper line at the beginning means a faster reaction rate.
Scientists measure reaction rates in several clever ways. They might measure the change in mass using an electric balance (perfect when gases escape), use a gas syringe to collect gas produced, or time how long it takes for a precipitate to form and obscure a cross drawn on paper underneath the flask.
Quick Tip: Remember that steeper curves = faster reactions, and all reaction graphs eventually flatten out when reactants are used up!