Final answer:
To show experimental concentration data fits a first-order reaction, you should plot time vs. concentration, which exhibits an exponential decrease or a straight line on a natural logarithm scale.
Step-by-step explanation:
The data that should be plotted to show that experimental concentration data fits a first-order reaction is time vs. concentration. For a first-order reaction, you would typically compare a graph of reactant concentration versus time, which should show an exponential decrease in concentration over time. Alternatively, you can plot the natural logarithm of reactant concentration versus time, which should yield a straight line if the reaction follows first-order kinetics. Additionally, knowing how to construct such graphs is part of analyzing reaction rates and determining the reaction order, which are key concepts in chemical kinetics.