Which best describes the transition from gas to liquid?

Energy must be removed because particles in liquid move more slowly.

Energy must be added because particles in liquid move more quickly.

Energy is neither added nor removed in this phase transition.

Energy is either removed or added, depending on the type of particles

Think of this equation.

liquid + energy = gas
You have the reverse of this which means energy must be removed from a gas to form the liquid.

The transition from gas to liquid is known as condensation.

The transition from gas to liquid is known as condensation. It occurs when a gaseous substance loses energy and particles come together to form a liquid. To better understand the process of condensation, we can look at the behavior of particles in a gaseous state.

In a gas, particles are moving freely and are far apart from each other, constantly colliding and bouncing off one another. However, when the gas loses energy (typically through cooling), the particles slow down and their kinetic energy decreases. As a result, the attractive forces between the particles become more pronounced, causing them to come closer together.

As the particles come closer, they begin to cluster and form liquid droplets. This clustering occurs due to the intermolecular forces, such as Van der Waals forces or hydrogen bonding, that are present between the particles. These forces pull the particles towards each other, bringing about a cohesive liquid state.

It's important to note that condensation can occur under various conditions, such as when water vapor in the air turns into liquid droplets to form clouds or when steam cools down and becomes water droplets on a cold surface. The exact conditions required for condensation depend on factors like temperature, pressure, and the specific substance involved.