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

• A. As temperature increases, density decreases.
• B. Temperature and density are not related.
• C. Density remains constant as temperature changes.
• D. As temperature increases, density increases.

Answer: (A)

Verified step by step guidance

1. Understand the concept of density, which is defined as mass per unit volume, mathematically expressed as \(\text{density} = \frac{\text{mass}}{\text{volume}}\).
2. Recognize that when temperature increases, most substances expand, meaning their volume increases while their mass remains constant.
3. Since mass stays the same but volume increases with temperature, the density, which is mass divided by volume, will decrease.
4. Therefore, the relationship between temperature and density for most substances is an inverse one: as temperature goes up, density goes down.
5. This explains why the correct description is: 'As temperature increases, density decreases.'