a student heats a liquid on a burner. what happens to the portion of liquid that first begins to warm? it…

Brief Explanations:

When a liquid is heated, its molecules gain kinetic energy and move more vigorously. This causes the molecules to spread out, increasing the volume of the liquid while the mass remains the same. According to the density formula $\rho=\frac{m}{V}$ (where $\rho$ is density, $m$ is mass, and $V$ is volume), an increase in volume with constant mass results in a decrease in density.

Answer:

It becomes less dense.