Calculation of entropy change for melting ice

In summary, to calculate the entropy change when 1 mole of ice at 268 K is melted to form water at 323 K, you can use the equation delta(S) = delta(Q)/T and take into account the enthalpy of fusion of ice at 273 K. However, since the temperature is not constant, you will also need to take into account the change in temperature by relating delta(Q) to temperature and integrating. This is an exam question from a previous year and the exam is tomorrow.
  • #1
chriswilson
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0

Homework Statement


Calculate the entropy change when 1 mole of ice at 268 K is melted to form water at 323 K. The heat capacity of ice is 3.8 J K-1 kg-1 and that of water is 75 J K-1 kg-1. The enthalpy of fusion of ice at 273 K is 6.02 kJ mol-1.

I know the entropy change by the melting of the ice is given by

delta(S)=delta(Q)/T

and that this is worked out by the enthalpy of fusion.

My question is how do I calculate the entropy change caused by the change in temperature since it is not at a constant temperature does this mean the first equation cannot be used?

Also this isn't a homework question it is an exam question from a previous year and my exam is tomorrow.
 
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  • #2
Relate delta(Q) to temperature and integrate.
 

1. What is entropy change for melting ice?

Entropy change for melting ice is a measure of the disorder or randomness of the molecules in a system as a solid substance, such as ice, transitions into a liquid state. It is a thermodynamic property that is related to the amount of heat energy absorbed or released during the process of melting.

2. How is the entropy change for melting ice calculated?

The entropy change for melting ice can be calculated using the equation ΔS = Q/T, where ΔS is the entropy change, Q is the heat energy transferred, and T is the temperature in Kelvin. For melting ice, Q represents the heat of fusion, which is the amount of heat energy required to melt one mole of ice at a constant temperature.

3. What factors affect the entropy change for melting ice?

The entropy change for melting ice is affected by the temperature at which the melting occurs, the amount of heat energy absorbed or released, and the properties of the substance (such as molecular structure and intermolecular forces). Additionally, any changes in pressure or presence of impurities can also affect the entropy change.

4. Why is the entropy change for melting ice important?

The entropy change for melting ice is important in understanding and predicting the behavior of substances during phase transitions. It is also a crucial factor in many industrial processes, such as food preservation and refrigeration, where controlling the melting and freezing of substances is essential.

5. Can the entropy change for melting ice ever be negative?

No, the entropy change for melting ice can never be negative. This is because the process of melting always results in an increase in disorder or randomness, as molecules in a solid state become more free and mobile in a liquid state. Therefore, the entropy change for melting ice is always positive.

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