Hotpack Cold Pack Lab

Essay by EssaySwap ContributorHigh School, 12th grade February 2008

download word file, 2 pages 3.0

Downloaded 10 times

Hot-Pack Cold-Pack Lab Purpose: -To determine the mass of ammonium nitrate (NH4NO3) needed to cause a 15-degree temperature drop for 200 ml of water.

-To determine the mass of Calcium Chloride (CaCl2) needed to cause a 60-degree temperature rise for 200 ml of water.

-To calculate standard molar enthalpy values of each compound.

Procedure: The first thing that needed to be done was measure out 200 mL of water and added it to the beaker. Next the initial temperature of the water was taken which turned out o be 19 degrees Celsius. The next thing that was done was to add the 5g of the solid to the water. The temperature change was then recorded in our notebooks. The next thing we were supposed to do was empty the beaker and add a new 200 mL of water to the beaker and repeat the whole process with an increased amount of the solid.

However the group did not follow this direction. The group did not empty out the water and added more of the solid to the original solid that was in the beaker. This action threw off the group?s calculations because the initial temp changed each time new solids were placed in the water. Based on common sense and comparing other group?s initial temperature, the group decided to change the initial temperature of each of the masses to roughly what the original initial temperature of 19 degrees. This was done to make the Data look somewhat correct. After all the data was collected the room was cleaned up and the data collecting of the CaCl2 and NH4NO3. The next step was to go to the computer lab to graph the data. Since the data was not originally correct the graph came out wrong. Instead of...