# AP Chemistry Exam: 2021 Results

The following data reflect the 134,316 students worldwide who took either the paper or the digital AP Chemistry Exam prior to June 12.

**AP Chemistry score distributions, 2019 vs. 2021**

The following table enables comparisons of student performance in 2021 to student performance on the comparable full-length exam prior to the covid-19 pandemic.

AP Score | 2019 | 2021 |
---|---|---|

5 | 11% | 11% |

4 | 17% | 16% |

3 | 28% | 24% |

2 | 23% | 25% |

1 | 21% | 24% |

Of these 134,316 students, 2 achieved a perfect score from all professors/readers on all free-response questions and correctly answered every multiple-choice question, resulting in the rare and impressive feat of earning all 100 of 100 points possible on an AP Chemistry Exam.

It’s also important to honor the work of students who did not qualify for a score of 3+, but who nonetheless developed basic understandings and skills in the course. As a reminder,** the most recent research on students who achieve a score of 2 in AP Chemistry** found that they earn significantly higher grades when taking the course in college than students with the same high school GPA, SAT score, race, and gender. And these outcomes are stronger for AP Chemistry students who receive a 2 than for students receiving 2s in most other AP subjects

**The May 7 In-School Paper Exam**

The largest exam date for AP Chemistry was May 7, so the following information is specific to the exam version administered on that date.

As usual, students scored significantly higher on the multiple-choice section than on the free-response questions.

**Multiple-choice section:**

- Course Units:
- AP Chemistry students demonstrated solid mastery of Units 4 (Chemical Reactions) and 5 (Kinetics), with ~15% of students earning a perfect score across all questions about these units.
- Students generally scored least well on Unit 1 (Atomic Structure and Properties), in which 5% of students answered all questions correctly and 8% answered none correctly; Unit 7 (Equilibrium), and Unit 8 (Acids and Bases).
- Big Ideas:
- Students generally demonstrated somewhat stronger understanding of Transformations and Energy than of Scale/Proportion/Quantity and Structure/Properties.
- Science Practices:
- Students demonstrated strongest skills on questions that required application of Science Practice 1 (Models and Representations; 11% of students answered every such question correctly) and Science Practice 4 (Model Analysis).
- Students’ scores would increase with more proficiency on questions related to Science Practice 2 (Question and Method)—somewhat lower than their performance on all other science practices.

The strongest results were typically on:

- Long Question 2 about silicon spectra; 9% of students earned 8–10 points out of 10 possible
- Long Question 3 about copper sulfate precipitation; 16% of students earned 8–10 points out of 10 possible.

**The Digital Exams**

To support student access, different testing modes—paper and digital—were essential. To protect exam security, many different exam versions were necessary. Accordingly, to provide students with similar opportunities for success regardless of which version they took, each version of the exam had to be analyzed separately by psychometricians to identify its unique difficulty level so that standards for scores of 3, 4, and 5 could then be separately identified for each exam version. Analyses focused on:

- Differences in the testing mode (paper or digital). For sections of the exam that proved easier to take digitally, the digital versions require more points for each AP score. For sections of the exam that proved easier to take on paper, the paper exam requires more points for each AP score.
- Differences in the difficulty of specific questions. When exam questions prove easier, more points are required for each AP score, and when exam questions prove more difficult, fewer points are required on one version than another.
- The net result for this year’s AP Chemistry Exams is that out of 100 points possible, some of the digital versions were equivalent in difficulty to the paper versions, and for those that were not:
- On the easiest digital version, a student needed to earn 2 more points to receive an AP score of 3 or higher than students who took the paper versions.
- On the hardest digital version, a student needed to earn 4 fewer points to receive an AP score of 3 or higher than students who took the paper versions.