Answer: It contains 88 g of zinc.
Step-by-step explanation:
Given: The ratio of zinc to copper is 4 to 13.
Ratio can be written as [tex]\dfrac4{13}[/tex]
A jar of the chemical contains 286 g of copper.
Let the quantity of zinc be x.
By using the direct proportion rule:[tex]\dfrac{x_1}{y_1}=\dfrac{x_2}{y_2}[/tex]
[tex]\dfrac{x}{286}=\dfrac{4}{13}\\\\ x=\dfrac{286\times4}{13}\\\\\Rightarrow\ x=88[/tex]
Hence, It contains 88 g of zinc.