Question

Classify the following changes as physical and chemical change

d) Blackening of silverware

Answer 1

• Chemical change involves a change in chemical composition.
• The exposure of silverware results in the reaction of Oxygen (${\mathrm{O}}_2$) with the Silver metal ( $\mathrm{Ag}$). As a result, the oxidation of Silver happens, and a totally new substance Silver oxide (${\mathrm{Ag}}_2\mathrm{O}$) is formed.
• The reaction is as follows:

$4\mathrm{Ag}+{\mathrm{O}}_2\to 2{\mathrm{Ag}}_2\mathrm{O}$

• Blackening of silver is a chemical change.