Question

question 7
1 pts
in the wise words of dan gable, an olympic gold medalist, \gold medals arent really made of gold. theyre made of sweat, determination, and a hard - to - find alloy called guts.\ at the melting point of gold 1064.18°c, the heat of fusion, δhfus, is + 12.55 kj/mol and at the normal boiling point of 2836°c, the heat of vaporization, δhvap, is + 334.4 kj/mol. how much heat must be applied to melt a 4.88 g sample of gold? report your answer in kilojoules to 3 sig figs, but do not include units in the answer.

Explanation:

Step1: Calculate the number of moles of gold

The molar mass of gold (\(Au\)) is \(M = 196.97\space g/mol\).
The number of moles \(n=\frac{m}{M}\), where \(m = 4.88\space g\).
\(n=\frac{4.88\space g}{196.97\space g/mol}\approx0.02487\space mol\)

Step2: Calculate the heat required to melt the gold

The heat of fusion \(\Delta H_{fus}=+ 12.55\space kJ/mol\).
The heat \(q=n\times\Delta H_{fus}\)
\(q = 0.02487\space mol\times12.55\space kJ/mol\approx0.312\space kJ\)

Answer:

\(0.312\)