Question

"optional question"

quation : Cacho) Catag taclag + Energy aw the energy diagram, consider the entire solvation process as a series of steps. the strongest attractive forces that exist in the 1) solid and 2) liquid that must be broken? 1) Lonic Banding 2) HNdoden-Band i 0ndipde forces 21 will breaking these forces be an endothermic or exothermic process? excimex 3) Name the attractive force (IPF) that is being created? 30n n e ces 4) Will this step be endothermic or exothermic? Xolhermic 5 Was the enthalpy of solution (the overall energy change) endothermic or exothermic? exothermic (Optional question) Use the calorimetry equation to calculate the energy of solution for calcium chloride. You will need the following values: - mass of the water in the test tube (assume a density of 1.00 g/ml) 5.09 temperature change of the water 1.7°C Specific heat capacity of water (4.184 J/g*C) Moles of calcium chloride dissolved 4.568 X10-3 mol Cable You are looking for an energy change with units of J/mol Write an equation for the process that took place in test tube 1 and include the energy term with the correct sign.

Answer 1

• If there is no heat loss due to surroundings, then,

heat released due to solvation (because it is exothermic) = heat absorbed by the water

Heat absorbed by water is,

$Q=ms\theta$

here, m = mass of water = 5.0 g, s = specific heat of water = 4.184 J / g. ^oC, $\theta$ = temperature change = 1.7 ^oC

$Q=(5.0g\times 4.184 J/g. ^oC\times 1.7 ^oC)=35.564J$

Now, heat released due to solvation of 4.568 x 10^-3 mol of CaCl₂ is 35.564 J

Thus, for 1 mol of CaCl₂

$=\frac{35.564}{4.568\times 10^{-3}}J.mol^{-1}=7785.464 J.mol^{-1}$

So, this is the energy change of heat change.

If you want the value of enthalpy change or $\Delta H_{solv}$, then put a negative sign before the value (bacause for exothermic process $\Delta H$ is negative).

• The equation for the process is:

$CaCl_2(s)\rightarrow Ca^{2+}(aq)+2Cl^-(aq)+7785.464J.mol^{-1}$