Which of the following is true about chemical exposure?

• A. Chemical exposure can lead to changes in the chemical composition of substances involved.
• B. Chemical exposure cannot cause any reactions unless the temperature is above 100°C.
• C. Chemical exposure only affects the physical state of a substance, not its chemical properties.
• D. Chemical exposure is always harmless if the chemical is a solid.

Answer: (A)

Verified step by step guidance

1. Understand the concept of chemical exposure: it refers to the contact between a chemical substance and a material or organism, which can potentially cause changes.
2. Recognize that chemical exposure can lead to chemical reactions, which may alter the chemical composition of the substances involved. This means new substances can form as a result of exposure.
3. Note that chemical reactions are not strictly dependent on temperature being above 100°C; reactions can occur at various temperatures depending on the chemicals and conditions.
4. Understand that chemical exposure can affect both physical and chemical properties, not just the physical state. For example, rusting of iron changes its chemical composition, not just its appearance.
5. Realize that the physical state of a chemical (solid, liquid, gas) does not guarantee harmlessness; solids can be reactive or toxic upon exposure.