Question

As part of a demonstration, Mr. Wadlow took flat copper wire and wrapped it around a pencil to make a coil. Then, he placed the coiled copper wire into a beaker of clear silver nitrate solution. After thirty minutes, gray particles collected on the copper, and the solution turned blue. What resulted from the combination of the copper wire and the silver nitrate solution?

a
a physical change, as demonstrated by the coiled wire
b
a chemical change, as demonstrated by the coiled wire
c
a physical change, as demonstrated by the gray particles and the blue solution
d
a chemical change, as demonstrated by the gray particles and the blue solution

Answer 1

d — a chemical change, as demonstrated by the gray particles and the blue solution.

Copper metal displaced silver ions from solution: Cu(s) + 2AgNO3(aq) → Cu(NO3)2(aq) + 2Ag(s). The silver metal deposits as gray particles and Cu2+ gives the blue solution — evidence of new substances (chemical change).