Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. T

Question

2 months ago

7

Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. T

he melting and freezing of paraffin inside the capsules in the material helps to regulate temperature. Paraffin wax begins to melt at 37°C37°C.(a) While the wax is melting, is the net flow of thermal energy from the wax to the surroundings or from the surroundings to the wax? Justify your answer.(b) Calculate the amount of thermal energy, in kJkJ, that is required to melt 15.215.2 grams of solid paraffin wax when the temperature of the surroundings is above the melting point of paraffin. (The molar mass of paraffin is 282.62g/mol282.62g/mol, and its molar heat of fusion is 48.78kJ/mol)(c) When paraffin wax melts, its density decreases. Provide a particle-level explanation of this observation.

Chemistry

1 answer:

Tems11 [2.7K] · Answer 1 · 2026-02-16T09:18:44+03:00

Answer:

(a)

Energy moves from the surroundings to the wax.

(b)

Q = 2.62 KJ

(c)

The density of a substance is characterized by the number of particles it contains per unit volume. When melting occurs, the intermolecular forces and bonds between the molecules or atoms weaken. This process leads to an increased distance between these particles. Consequently, the number of particles per unit volume diminishes, which reduces the density of the substance.

Explanation:

(a)

During melting, the solid substance needs energy to break bonds between its molecules or atoms.

So, while wax melts, the net thermal energy flows from the surroundings into the wax.

(b)

The energy needed to melt solid paraffin wax is defined by the equation:

Q = nC

where,

Q = energy quantity

C = Molar Heat of Fusion = 48.78 KJ/mol

n = number of moles = Mass in grams / Molar Mass = (15.2 g)/(282.62 g/mol)

n = 0.0538 mol

Thus,

Q = (0.0538 mol)(48.78 KJ/mol)

Q = 2.62 KJ

(c)

The density of a substance is defined as the number of particles packed in a unit volume. As the substance melts, the attractive forces between its molecules weaken. This results in an increase in separation between the molecules or atoms. Consequently, the number of particles in a unit volume is reduced, leading to a decrease in the substance's density.

Some building materials contain small capsules filled with paraffin wax to improve the insulating properties of the materials. T

Response:

To elaborate:

Step 1: Write the balanced reaction equation

Step 2: Calculate the moles of NaOH