Question

A beaker of water is heated to boiling by a Bunsen burner. Would adding another burner raise the temperature of the boiling water? Explain.

Short answer

Adding another burner won't raise the boiling water's temperature.

Step-by-step solution

Understanding Boiling Point

Understand that the boiling point of water at sea level is 100°C (212°F). When water is boiling, it remains at this temperature and does not get hotter, regardless of the heat source.

Concept of Adding More Heat

Adding more heat to the boiling water only causes it to boil faster and turns more liquid water into steam, instead of increasing the temperature.

Constant Temperature During Phase Change

Recognize that during a phase change, such as from liquid to gas, the temperature of the substance does not increase even if additional heat is applied. This is because the added energy is used to break the intermolecular bonds rather than increasing the temperature.

Key concepts

Phase Change

A phase change is when a substance transitions between different states of matter, such as from solid to liquid or liquid to gas. For water, the phase change occurs when it moves from its liquid state to steam during boiling. During this process, even though heat energy continues to be added, the temperature remains constant at the boiling point. This is because the energy is used to change the phase rather than increase the temperature. A phase change is a critical concept to understand when working with boiling water, as it explains why further heating does not increase the temperature but rather accelerates the transition into steam.

Intermolecular Bonds

Intermolecular bonds are the forces that hold molecules together within a substance. In water, these bonds are primarily hydrogen bonds. During boiling, energy from the heat source is used to break these intermolecular bonds. As the water molecules gain enough energy to break free from one another, they transition into the gaseous state. The breaking of intermolecular bonds is a crucial part of the phase change process. The energy required to break these bonds, known as latent heat, does not increase the temperature but facilitates the transition from liquid to gas.

Heat Transfer

Heat transfer is the process of energy moving from a hotter object to a cooler one, a fundamental process in boiling water. When a Bunsen burner heats the beaker of water, heat is transferred to the water, increasing its energy. However, once the water reaches its boiling point, additional energy is absorbed without raising the temperature further. Instead, the energy is utilized in the phase change, transforming water into steam. Understanding heat transfer helps clarify why the temperature of boiling water does not rise beyond its boiling point, despite continued heating.

Bunsen Burner

A Bunsen burner is a commonly used heat source in laboratories, providing a controllable flame to heat substances such as water. It operates by mixing gas with air to produce a clean, hot flame. When used to heat water to boiling, the burner ensures an even and reliable transfer of heat. However, introducing a second Bunsen burner will not increase the boiling water's temperature. It will simply provide more energy for the phase change, making the water turn to steam more quickly. The efficiency, safety, and control of Bunsen burners make them ideal for many scientific experiments.

Temperature Control

In scientific experiments, maintaining precise temperature control is essential for accurate results. During boiling, controlling the heat source ensures that the temperature remains consistently at the boiling point. This constant temperature is crucial during phase changes, as it allows for the proper transition from liquid to gas without overheating. When using devices such as a Bunsen burner, adjusting the flame size helps control the amount of heat applied. While more burners might speed the phase change, they won’t alter the temperature, demonstrating the importance of understanding how temperature control differs from merely increasing heat.