It will take 11.11 min to melt the sample. ∆H fus = 180 J/g.
To determine the time required to melt the sample, the time required to heat the sample from initial temperature to its melting point, and then the time required to melt the sample both needs to be considered.
The heat required to heat the sample to its melting point is calculated in part
The heat required to melt the sample needs to be calculated.
Melting is the phase change of solid to liquid at -20°C, therefore, the heat required to melt the sample can be determined as,
q2= m× ∆H fus
= 25 g × 180 J/g
= 4500 J
Thus, the total heat required for this phase change is q1 + q2 = 500 J + 4500 J = 5000 J.
The Rate of heating = 450 J/min
450. J = 1 min
5000 J = ? min
Hence, melting the sample takes a total of 11.11 min.
Learn more about ΔHfus here:-https://brainly.com/question/17086277
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