What is the result of heating water in a closed system?

In a closed system, when water is heated, the temperature of the water increases. As the temperature rises, the kinetic energy of the water molecules also increases, causing them to move more rapidly. This increased movement can lead to an increase in pressure within the closed system, as the molecules collide with the walls of the container with greater force and more frequently.

The concept of a closed system is critical here, as it means that no matter or energy can be exchanged with the surroundings. This is in contrast to an open system, where heat might escape and stabilize the temperature and pressure. Since the water cannot expand or escape in a closed environment, the pressure builds up as the heat causes the water to try to expand.

Therefore, the correct answer is that pressure increases when water is heated in a closed system.