Calculate the change in entropy that occurs in the system when 1.00 mole of isopropyl alcohol (C₃H₈O) melts at its melting point (-89.5 °C). See Table 12.9 for heats of fusion.

Video transcript

Hello everyone today. We are being asked to consider a system with 1.26 moles of acetone and asked to calculate the change in entropy that occurs in the system when it melts. If its melting point is negative, 94.8°C. And it's heat of fusion is 5. kg per mall. And so the first thing I want to do is we want to consider the equation for our total entropy which is dealt to us is equal to the infill p of a reversible reaction over temperature. So what we're gonna do is we're gonna plug in our values and so for Q We're gonna have our 5.69 kill jules per mole. And since the answer has to be in terms of Jules, we must convert kill jewels, two jewels and we're going to use the conversion factor that one killer jewel is equal to 10 to the third jewels. We are then going to divide this by the total temperature. And as it's seen in the question, since it is in C, we must convert to Kelvin and we simply do that by adding to 73.15 Kelvin. This gives us an answer of 31. jewels per mole kelvin But we're not done yet because we have this 1.26 moles to take care of. And so what we're gonna do is we're gonna take our 31. jewels per mole Kelvin. And to get rid of the units in the denominator, we're going to simply multiply this number by 1. moles. Our units of moles are going to cancel out. We're gonna be left with a final answer of 40 . Jewels Per Kelvin. I hope this helped, and until next time.