Chapter 11: Problem 137
A student heated a beaker of cold water (on a tripod) with a Bunsen burner. When the gas was ignited, she noticed that there was water condensed on the outside of the beaker. Explain what happened.
Short Answer
Expert verified
Water vapor in the air condensed on the cool surface of the beaker.
Step by step solution
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Key Concepts
These are the key concepts you need to understand to accurately answer the question.
Bunsen Burner
In many science laboratories, a Bunsen burner is an essential piece of equipment.
It provides a controlled flame, used for heating substances or materials.
The Bunsen burner operates using a mixture of gas and air, which can be adjusted to produce either a luminous or a non-luminous flame.
When igniting a Bunsen burner, one typically opens the gas valve and uses a spark or match to light it. The burner is designed with an adjustable collar that allows you to control the air flow. This, in turn, modifies the flame's temperature and characteristics.
- A non-luminous flame (blue) is hotter, allowing efficient heat transfer. - A luminous flame (yellow) is cooler, with incomplete combustion happening. Bunsen burners are versatile and provide instant heat, making them ideal for heating water, as seen in our exercise. The flame directly heats the bottom of the beaker, increasing the water's temperature inside.
When igniting a Bunsen burner, one typically opens the gas valve and uses a spark or match to light it. The burner is designed with an adjustable collar that allows you to control the air flow. This, in turn, modifies the flame's temperature and characteristics.
- A non-luminous flame (blue) is hotter, allowing efficient heat transfer. - A luminous flame (yellow) is cooler, with incomplete combustion happening. Bunsen burners are versatile and provide instant heat, making them ideal for heating water, as seen in our exercise. The flame directly heats the bottom of the beaker, increasing the water's temperature inside.
Water Vapor
Water vapor is an invisible form of water that exists in the air all around us.
It is a crucial part of the water cycle and is created whenever water evaporates.
In the exercise scenario, the air around the beaker contains water vapor.
When cold water in the beaker is heated by the Bunsen burner, the heat from the flame transfers to the water. However, during the early stages, not all the heat is absorbed by the water, leading to a cool beaker surface.
The air, warmed by surrounding conditions and moisture, when in contact with this cooler beaker, allows the water vapor to condense. Condensation happens as the cooler surface draws heat out from the water vapor, turning it back into droplets of liquid.
When cold water in the beaker is heated by the Bunsen burner, the heat from the flame transfers to the water. However, during the early stages, not all the heat is absorbed by the water, leading to a cool beaker surface.
The air, warmed by surrounding conditions and moisture, when in contact with this cooler beaker, allows the water vapor to condense. Condensation happens as the cooler surface draws heat out from the water vapor, turning it back into droplets of liquid.
Heat Transfer
Heat transfer is the process by which thermal energy is moved from one object to another.
In our exercise, there are several forms of heat transfer happening.
- **Conduction**: This occurs as the Bunsen burner's flame heats the beaker. The heat from the flame transfers through the solid material of the beaker to the water inside. - **Condensation Role**: The cool surface of the beaker attracts water vapor from the surrounding air. As the water vapor touches the cooler surface, heat is removed, causing the vapor to change back into liquid water droplets. The concept of heat transfer explains why the surface of the beaker collects condensation, as energy changes states and moves between substances.
- **Conduction**: This occurs as the Bunsen burner's flame heats the beaker. The heat from the flame transfers through the solid material of the beaker to the water inside. - **Condensation Role**: The cool surface of the beaker attracts water vapor from the surrounding air. As the water vapor touches the cooler surface, heat is removed, causing the vapor to change back into liquid water droplets. The concept of heat transfer explains why the surface of the beaker collects condensation, as energy changes states and moves between substances.
Latent Heat
Latent heat refers to the energy absorbed or released by a substance during a phase change, such as from liquid to vapor or vice versa.
It is crucial in understanding why water vapor condenses on the beaker in the process.
When the surface of the beaker is cooler compared to the surrounding air, the water vapor loses energy as it changes from gaseous to liquid state. This release of energy in the form of latent heat causes the water droplets to form.
- **Energy Release**: As water vapor condenses, it releases latent heat to the cooler surface. - **Visible Result**: The released heat manifests as water droplets on the cooler beaker surface. Latent heat is vital in this process, making the cycle of vapor to liquid visible, as heat is exchanged during phase change.
When the surface of the beaker is cooler compared to the surrounding air, the water vapor loses energy as it changes from gaseous to liquid state. This release of energy in the form of latent heat causes the water droplets to form.
- **Energy Release**: As water vapor condenses, it releases latent heat to the cooler surface. - **Visible Result**: The released heat manifests as water droplets on the cooler beaker surface. Latent heat is vital in this process, making the cycle of vapor to liquid visible, as heat is exchanged during phase change.
