Test Tube 1: Analysis
a) Write the equation from your lab notebook for this dissolution
CaCl2(S) + 2H2O(s) → Ca(OH)2(aq) + HCl(g)
b) Use the recorded values in your lab notebook to calculate both the molarity and the molality of the solution. (the density of water at room temperature is 0.997 g/mL)
c) Insert the graph of your temperature change and report the ΔT.
d) Sketch or insert an image of the matching energy diagram (see the figure in the lab for an example). Label as endothermic or exothermic. Endothermic
e) Use the heat capacity of water (4.184 J/g°C) to calculate the energy change of the water in Joules
f) Consider the entire solvation process as a series of steps in the energy diagram and answer these questions. Name the strongest attractive forces that exist in the 1) solid and 2) liquid that must be broken?
Will breaking these forces be an endothermic or exothermic process?
Name the attractive force (IPF) that is being created?
Will this step be endothermic or exothermic?
Was the enthalpy of solution (the overall energy change) endothermic or exothermic?
Label the energy diagram with this answer
Test Tube 2 Analysis - Part A:
a) Write the equation from your lab notebook for this dissolution.
b) Use your recorded data to calculate the molarity and the molality of the solution.
c) Insert the graph of your temperature change and report the ΔT
d) Sketch or insert the matching energy diagram (see the figure in the lab for an example). Label the energy diagram as endothermic or exothermic.
e) Use the heat capacity of water (4.184 J/g°C) to calculate the energy change of the water in Joules
Test Tube 2 Analysis- Part B:
Rewrite the equation for the supersaturated solution as it cooled down from your lab notebook
K+NO3(s) → K(aq) + NO3(aq) + Energy
State where the energy in this equation is coming from and where it is going as potassium nitrate crystallizes. Be sure to identify if the forms of the energy as kinetic or potential energy.