Question

an amount of nitrogen undergoes a physical change and increases its volume. what can be known about this physical change? the boiling point of the nitrogen increased. the mass of nitrogen increased. the color changed. the density changed.

Explanation:

The density formula is $
ho=\frac{m}{V}$, where $
ho$ is density, $m$ is mass and $V$ is volume. In a physical - change, mass is conserved. Since volume ($V$) increases and mass ($m$) remains the same, density ($
ho$) must decrease. Boiling point is a characteristic property and doesn't change just because of a volume increase in a simple physical - change. Mass is conserved in physical changes. Nitrogen is a color - less gas under normal conditions and a simple volume increase won't change its color.

Answer:

D. The density changed.