P5.4—Dealing with data

Choose the calculation or presentation that matches the question: means for repeats, percentage change or error for comparisons, a gradient for a rate, and a graph with labelled axes and suitable significant figures.

Keep raw and processed data separate, show substitutions and units, and round only at the end. For y = mx + c, interpret m and c in the chemical context rather than reporting numbers alone.

A 10.0% increase from 2.00 to 2.20 is calculated from (0.20/2.00)×100; a rate is the gradient of gas volume against time, not the final volume.

A calculator result is not automatically the correct quantity; check whether the question asks for a mean, percentage, gradient or intercept.