2021, Question 4 · Short answer · 4 points · about 9 minutes
Iron oxidation in a hand warmer
Use temperature data and reaction enthalpy to estimate reacting iron and compare the effects of changing its mass.
Lessons this question draws on
1 Read the question
The question is College Board's, from the 2021 exam. It starts on page 14 of the PDF. College Board no longer posts this exam, so it opens from the copy of College Board's PDF that the Internet Archive saved on May 5, 2026.
Open Question 4 (PDF, page 14)
2 Write your answer
Answer each part the way you would on the exam, in full sentences, with your work shown. Your writing saves as you type.
3 Score it
Score your answer against College Board's scoring guidelines, one point at a time. Give yourself a point only when your answer says what the guideline asks for.
Scoring guidelines (PDF, page 8) What the exam readers saw (Chief Reader report)
Question, scoring guidelines and Chief Reader report: College Board, from the Internet Archive. The title, summary are ours.