[chem] interpretation of results for practical investigation

diff --git a/chem/calorimetry-prac-results.xlsx b/chem/calorimetry-prac-results.xlsx
index 63bb49e6f8dcb36a8651cc21f6c5bb551f462e33..2b269207cc004bbed1a17d71e189a5cf8f35325d 100644 (file)
Binary files a/chem/calorimetry-prac-results.xlsx and b/chem/calorimetry-prac-results.xlsx differ

diff --git a/chem/practical-investigation.md b/chem/practical-investigation.md
index 459aaddebbc4a52552ba721df8e3ed33b92c85cb..7652a7955f358972eb9947d3fdb915fb2f85b67d 100644 (file)
--- a/chem/practical-investigation.md
+++ b/chem/practical-investigation.md
@@ -1,4 +1,4 @@
-# How do functional groups affect the enthalpy of neutralisation?
+# How does the enthalpy of neutralisation vary for different sodium salts?
 
 ## Method
 
@@ -6,3 +6,16 @@ The calorimeter was first calibrated with 80.0 mL of deionised water. The water
 
 After emptying and rinsing the calorimeter, 40.0 mL of 1.0 M NaOH was added to the calorimeter and its temperature recorded. 80.0 mL of 1.0 M HCl was then addedd and its temperature also recorded. Power was applied to the calorimeter for exactly 180 seconds, and the highest temperature of the solution was recorded. The solution was constantly mixed to minimise the error due to slow convection.
 The previous procedure was repeated for the other two compounds, Na2CO3 and Na2SO4.
+
+## Results
+
+After three attempts at calculating the heat capacity of the calorimeter, an average value for the calibration constant, C_cal, equal to 286.0 J/K, was obtained. This was calculated using the second and third calibration trials (the first one was an outlier due to timing inaccuracy and possibly residue in the calorimeter).
+
+/\H = C_cal * /\T_avg / n
+
+where n is the number of mol of NaOH, in this case equal to the volume in litres (since it is a 1M solution).
+
+## Discussion
+
+Assumed density of all solutions is 1 g/mL (=> mass = volume)
+Assumed heat capacity of solution is the same as water (4.18 JK/g)