Which of the following substances contains silica (SiO_2)?

• A. Quartz
• B. Table salt
• C. Copper metal
• D. Ice

Answer: (A)

Verified step by step guidance

1. Understand that silica is the chemical compound silicon dioxide, which has the formula \(\mathrm{SiO_2}\).
2. Recognize that quartz is a mineral composed primarily of silicon dioxide, so it contains silica.
3. Identify that table salt is sodium chloride (\(\mathrm{NaCl}\)), which does not contain silicon or oxygen in the form of silica.
4. Know that copper metal is an elemental metal (\(\mathrm{Cu}\)) and does not contain silica.
5. Realize that ice is solid water (\(\mathrm{H_2O}\)) and does not contain silicon or oxygen in the form of silica.