Question

The molar heat of fusion of platinum (pt) is 4.700 kcal/mol. How much heat must be added to 85.5 g of solid platinum at its melting point to completely melt it? Use the formula q = n��h.

Answer 1

Approximately 2.059 kcal of heat must be added to melt 85.5 g of platinum using the formula q = n×Δh, with the molar heat of fusion and the number of moles calculated based on the platinum's mass and molar mass.

Step-by-step explanation:

The question is asking how much heat (q) is required to melt 85.5 g of platinum at its melting point, given its molar heat of fusion is 4.700 kcal/mol. To find this, we need to calculate the number of moles (n) of platinum, then use the formula q = n×Δh.

First, we calculate the number of moles of platinum:

n = mass(g) / molar mass(g/mol)

Platinum has a molar mass of approximately 195.08g/mol.

n = 85.5g / 195.08g/mol ≈ 0.438 mol

Now we apply the formula to find the heat (q) required to melt the platinum:

q = n×Δh

q = 0.438 mol × 4.700 kcal/mol ≈ 2.059 kcal

Therefore, to melt 85.5 g of platinum at its melting point, approximately 2.059 kcal of heat must be added.