Final answer:
To find the mass of zinc in a jar that contains 760 grams of copper, given the zinc to copper ratio is 4 to 19, we calculate that the jar contains 160 grams of zinc.
Step-by-step explanation:
In a certain chemical, the ratio of zinc to copper is 4 to 19. If a jar of the chemical contains 760 grams of copper, to find how many grams of zinc it contains, we use the concept of ratios. The total ratio parts are 4 (zinc) + 19 (copper) = 23 parts. Since 19 parts correspond to 760 grams of copper, we can calculate the value of one part:
1 part = 760 grams / 19 = 40 grams
Now, to find the grams of zinc which correspond to 4 parts:
Zinc mass = 4 parts * 40 grams/part = 160 grams
Therefore, the jar contains 160 grams of zinc.