How much energy is released when 75.2 g of water freezes?

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Identify the process: Freezing of water is a phase change from liquid to solid, which releases energy in the form of heat.

Determine the heat of fusion for water: The heat of fusion for water is approximately 334 J/g. This is the amount of energy released when 1 gram of water freezes.

Calculate the total energy released: Multiply the mass of the water (75.2 g) by the heat of fusion (334 J/g) to find the total energy released.

Set up the equation: Energy released = mass of water × heat of fusion.

Substitute the values into the equation and solve for the energy released.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Heat of Fusion

The heat of fusion is the amount of energy required to change a substance from solid to liquid at its melting point, or vice versa. For water, this value is approximately 334 joules per gram. When water freezes, it releases this amount of energy per gram, which is crucial for calculating the total energy released during the freezing process.

Mass and Energy Relationship

The relationship between mass and energy is fundamental in thermodynamics. In this context, the mass of the substance (water) directly influences the total energy released during a phase change. By knowing the mass of water and the heat of fusion, one can calculate the total energy released when the water freezes.

Phase Changes

Phase changes refer to the transitions between solid, liquid, and gas states of matter. Freezing is a phase change where a liquid becomes a solid, and it involves energy transfer. Understanding the nature of phase changes helps in predicting the energy dynamics involved when substances transition between different states.

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