Question

select the correct answer
a sample of physical evidence was heated with dry cupric oxide. the issuing gas turned lime water milky. which element does the physical evidence contain?
a. oxygen
b. hydrogen
c. carbon
d. bromine
e. chlorine

Explanation:

When a substance is heated with dry cupric oxide and the resulting gas turns lime - water milky, it indicates the presence of carbon dioxide gas. Carbon - containing substances, when oxidized by cupric oxide, can produce carbon dioxide. Lime - water (calcium hydroxide solution) reacts with carbon dioxide to form calcium carbonate, which is insoluble and makes the lime - water turn milky.

Answer:

C. carbon