Which statement best describes the relationship between temperature and the density of most substances?

• A. Temperature has no effect on the density of substances.
• B. As temperature increases, density generally increases because substances contract.
• C. As temperature increases, density remains constant for all substances.
• D. As temperature increases, density generally decreases because substances expand.

Answer: (D)

Verified step by step guidance

1. Recall the definition of density, which is given by the formula \(\text{density} = \frac{\text{mass}}{\text{volume}}\).
2. Understand that when temperature increases, most substances expand, meaning their volume increases while their mass remains constant.
3. Since mass stays the same and volume increases, the density, which is mass divided by volume, will decrease.
4. Recognize that this relationship is generally true for most substances, except for some anomalies like water near 4°C.
5. Therefore, the correct description is that as temperature increases, density generally decreases because substances expand.