Chemistry

This is a redox problem where you need to track electron transfer carefully. $\text{Cu}_3\text{P}$ contains copper in the +1 state and phosphorus in the −3 state—both are reducing agents. You must oxidize both elements to their final products ($\text{Cu}^{2+}$ and $\text{P}^{5+}$), count the total electrons lost, then use the reduction of dichromate ($\text{Cr}^{6+} \to \text{Cr}^{3+}$) to find how many moles of $\text{K}_2\text{Cr}_2\text{O}_7$ are needed.

This is a redox problem where you need to track electron transfer carefully. $\text{Cu}_3\text{P}$ contains copper in the +1 state and phosphorus in the −3 state—both are reducing agents. You must oxidize both elements to their final products ($\text{Cu}^{2+}$ and $\text{P}^{5+}$), count the total electrons lost, then use the reduction of dichromate ($\text{Cr}^{6+} \to \text{Cr}^{3+}$) to find how many moles of $\text{K}_2\text{Cr}_2\text{O}_7$ are needed.