This is the boss. No calculator — the masses land on clean multiples of the molar mass, the enthalpies are round, and the percents are the friendly kind. One fuel sample, one long report, and every answer feeds the next: the balance gives grams, $n = \dfrac{m}{M}$ counts them, $q = n\,\Delta H$ predicts the heat, and the percent-yield referee compares the calorimeter's catch to the prediction. Write each line down as you go — one early slip burns all the way through the report.

Everything from the chapter rides in it. 5★ under par here is the chapter crown. Bunsen burners off, eyes on your own page.