Some building materials contain small capsules filled with paraffin wax to improve the insulating pr — Thermodynamics Chemistry Question
Problem Context
Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. The melting and freezing of paraffin inside the capsules in the material helps to regulate temperature. Paraffin wax begins to melt at 37°C.
Model Answer
Thermal energy flows from the surroundings to the wax. Melting is an endothermic process that requires the flow of thermal energy into the material for the phase change to occur.
1 point is earned for the correct answer with an appropriate justification.
Model Answer
15.2 g * (1 mol / 282.62 g) * (48.78 kJ / 1 mol) = 2.62 kJ
1 point is earned for the correct calculation.
Model Answer
In liquid paraffin, the average distance between molecules is greater than in the solid state. Thus, the same number of molecules occupies a larger volume, and the density decreases.
1 point is earned for citing the greater average distance between particles.
1 point is earned for relating the increased volume to decreased density.