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Topic: Relationship between freezing point depression and specific heat capacity  (Read 2109 times)

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Offline GodAmongMen

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So I have to come up with a lab that counts for 20% of my final mark. I am thinking to do something with road salt, and was wondering if there is a relationship between freezing point depression of an NaCl and water solution and its specific heat capacity.

 If there is isn't, are there any other interesting properties of salt (or really anything cause labs start next week and I am getting desperate) that I can explore within a high school environment?

Thanks guys would really appreciate it!

Offline Borek

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Re: Relationship between freezing point depression and specific heat capacity
« Reply #1 on: November 02, 2016, 03:16:23 AM »
To keep close to your original idea: what about experimental determination of the van 't Hoff factor for several salts and at different concentrations? The real relationship isn't as easy as it may seem.
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Offline Enthalpy

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Re: Relationship between freezing point depression and specific heat capacity
« Reply #2 on: November 03, 2016, 06:44:27 PM »
Corrosion by chloride ions?

Put aluminium wrap foil in an acid (try a few low concentrations) without chloride, observe the time to punch through the foil. Add salt, check if corrosion accelerates.

Water saturated with NaCl, without any acid, takes few days to punch through an aluminium wrap foil.

Hygroscopicity of salt?

Find sensitive scales. Put the salt in a hot oven for long. Pou in on the scales. Wait for a few days, observe meanwhile if the mass increases by the absorption of air moisture.

Additivity of volumes ?

Find the density of (a block of) salt. Measure the mass of your salt powder, deduce its volume. Do the same with water (remember 1000kg/m3 is at +4°C only). Dissolve. Observe if the volumes have added or not, and by how much. Needs accurate volume measures, and you must prevent evaporation. It may be easier to pour the coarse salt in water, observe the volume, stir to dissolve, compare.

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