In chemistry, CPR can stand for two different things: Corrosion Penetration Rate or Calibrated Peer Review.

• Corrosion Penetration Rate (CPR): CPR is defined as the speed at which any metal in a specific environment deteriorates due to a chemical reaction. It is a measure of the corrosion rate or the ratio of the material removal as a consequence of the chemical action. CPR is usually expressed in units of miles per year (mpy) or millimeters per year (mm/yr) and is calculated by measuring the reduction in the thickness of the material per time unit.

• Calibrated Peer Review (CPR): CPR is a web-based program used in chemistry courses to assess students writing and critical evaluation skills. In this program, students write essays on science and chemistry topics, which are then peer-reviewed and graded by other students. The grading criteria vary from course to course, but typically include factors such as scientific accuracy, clarity, and organization.

It is important to note that these two meanings of CPR are unrelated to each other and refer to different concepts in chemistry.