In this chapter, the police are asking your students to analyze new evidence to determine the type of chemical substances present and possibly match the substances at the crime scene to the suspects involved in the case. This performance assessment consists of four parts. In the first part, your students will analyze the chemical samples collected at the crime scene to determine the composition of each sample. In the second part, your students will match the chemical substances with the suspects in the case. In the third part, your students will determine the amount of moles of each substance. Finally, in the fourth part, your students will perform some calculations to determine the unknown chemical sample and potentially link it to a suspect.