[Chevalier]

I have attempted this problem for a while, and my approaches have yielded no results. My attempted strategies will be below. However, first here is the total question text to make sure I miss nothing.

"Your boss is also considering marketing this product to lumberjacks. As an aficionado of Paul
Bunyan stories in his youth, he is convinced that while lumberjacks may sometimes be without
water, they will always have an ample supply of maple syrup. If the same amount of CaCl2 is
added to equal volumes of water and maple syrup, which will have the higher temperature: the
water or the maple syrup? Assume the CaCl2 dissolves completely and that both the water and the maple syrup are at 32°F. Explain your reasoning, including necessary calculations.

 The thermodynamic properties of maple syrup are often overlooked in the chemical literature, but
the following data have been reported:
  density: 1.325 g/ml 
  specific heat: 2.01 J/g°C
  viscosity: 3200 cP (water: 1.0 cP) "

First I assumed 50ml CalCl2 and 50ml water/maple syrup. Using density I calculated maple syrup's actual mass to be 66.25g. With water's still being 50.

Next I attempted to use the specific heat capacity while assuming the same, and thus assumable energy was used and solve for the tfinal using the differing masses.

csp= qp/(m deltaT) [deltaT= tfinal-tinitial]

I received a number smaller than tinitial for my tfinal. So I assume my method was wrong.

I then attempted to find the Cp molar heat capacity and use it somehow. After finding it, I realized I didn't know the mass of one mole of maple syrup. A dead end.

Next I tried looking for equations that link viscosity and temperature. I know of the basic > temp means < viscosity. I assumed there was a numerical relationship though. A dead end.

I then tried to find the actual heat used by doing my balanced Eq for CalCl2 + Water. However, I could not do the same for maple syrup since I do not know the chemical formula for it and could not find it. A dead end.


Please help. I have honestly tried, and come up with nothing. Thank you so much. I feel like I must be missing something major. The lecture slides haven't been any help.

[DrCMS]

How do the specific heat capacities of water and maple syrup compare?

[Chevalier]

Maple syrup's is pretty much half of water's which would imply it takes half the amount of energy to change the temperature by 1 degree. However, I'm not sure how to take into account the differing viscosity and density.

[DrCMS]

Maple syrup's is pretty much half of water's which would imply it takes half the amount of energy to change the temperature by 1 degree.

So the same amount of energy acting on equal mass of water or maple syrup would raise the temperature of the maple syrup about twice as much as water.

In your question you do not have equal masses you have equal volumes so you need to use the density to work out the relatives masses of each.

Why do you think the viscosity is important?

[Chevalier]

Wouldn't the fact that the viscosity is that much higher mean that the intermolecular force is stronger and therefore more energy would be required for particles to move and therefore more would be required for the temperature to be raised by 1 degree?

[Chevalier]

Sorry for the double post, but I now basically did my first method except using X as the energy value and found.

Delta T to be (X/133.16) in maple syrup and (X/210) in water. Is this enough to support my assertion of syrup having the higher temperature?

Ignoring viscosity as your post implies. Thank you so much for your reply though!

[DrCMS]

Wouldn't the fact that the viscosity is that much higher mean that the intermolecular force is stronger and therefore more energy would be required for particles to move and therefore more would be required for the temperature to be raised by 1 degree?

NO  - you are given the specific heat and is is lower for maple syrup so less energy is required to raise the temperature compared with the same mass of water.  Do not try to over think things when you are given the actual data.

With a specific heat half that of water but a density only a third higher the maple syrup will end up hotter for the same amount of energy input.

Viscosity is irrelevant for this question.