Chapter 10, Problem 88RQ

A mixture of ${\text{N}}_{\text{2}}{\text{, O}}_{\text{2}}{\text{, and CO}}_{\text{2}}$ Has a total pressure of 740 torn In this mixture the partial pressure of ${\text{N}}_{\text{2}}$ is 12.0 cm Hg and the partial pressure of ${\text{O}}_{\text{2}}$ is 4.00 dm Hg. What is the partial pressure of the ${\text{CO}}_{\text{2}}$?