Question

what happens to the particles of a substance as its temperature increases?
they move faster.
they move slower.
they lose some energy.
they move in a circular direction.

Explanation:

When the temperature of a substance increases, according to the kinetic - molecular theory, the average kinetic energy of the particles in the substance increases. Kinetic energy is related to the motion of particles (\(KE=\frac{1}{2}mv^{2}\), where \(m\) is the mass of the particle and \(v\) is the velocity). Since the mass of the particles (assuming no chemical change, so the identity of particles remains the same) does not change, an increase in kinetic energy means an increase in the speed (\(v\)) of the particles.

Answer:

They move faster.