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Identification of an Unknown by its Specific Heat Capacity

 e1-05 Determination of an Unknown Based on its Specific Heat Capasity

Your Mission:
To determine the identity of an unknown using its calculated specific heat capacity, observations and logical inferences.

In this lab you will heat an unknown substance for one minute in an attempt to identify its identity.  To gather this data you will use the temperature probe of logger pro.  Firstly you must obtain a sample (labeled 1-8). On this beaker, its mass will be shown. In order to determine the mass of the liquid inside the beaker you must take the weight of the beaker with the unknown substance in it. By subtracting the stated mass of the beaker, you will be able to determine the mass of the unknown.


Next, turn on your hot plate to full (10 for the Red 'Fisher' hot plates and 6 for the grey Corning hot plates). They must first come up to full heat so leave them on without placing the beaker on them for a minimum of 3 minutes. During this time you can download the logger pro template file (SHClab.cmbl) which will be used to record the temperature of your sample.

Once the hot plate has reached its full temperature, place the beaker containing the unknown on top and place the temperature probe into the substance. You must again wait for a minute before hitting 'collect' to allow the probe to warm up to the temperature of the substance. Once hitting collect, the lab pro will automatically record the temperatures for exactly one minute. This will be displayed as a graph. 

 

Like previous labs, you will need to uncheck "connect points" in graph options, and add a line of best fit (LINEAR). The slope of this line will tell you how much the temperature changed in 60 seconds. This will be a critical piece of information to calculate the specific heat capacity of the substance.

Given that the power of the hotplates is 59.238w for the 'Fisher' hot plate and 54.708w for the 'Corning' one, calculate the specific heat capacity of the substance. You can then use this along with other "observations" / logic to determine the unknown by comparing it with known values (start here).

Questions:

  1. Using clear calculations with the proper D.E.S.S. format, show all of your calculations to arrive at a SHC for your substance.
     

  2. Hypothesize what your substance may be. Be sure to use your calculated value as well as any logical inferences / observations about your material. Be specific and detailed.

 Instructions:
In a word document, include the fully labeled graph of your heating data, and COMPLETE answers to the questions.

Be sure to include your name and DO NOT include the questions in your assignment (it will show up as plagiarized on www.turnitin.com).

Submit to www.turnitin.com as instructed in class..