1) Does the solubility of borax in water increase or decrease astemperature increases? What experimental evidence supports youranswer?

(2) Is the dissolution of borax in water an exothermic orendothermic process? What experimental evidence supports youranswer?

(3) Is the dissolution of borax in water a temperature dependentreaction or is it spontaneous at all temperatures at which water isliquid? Briefly explain.

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Postlab Help- these are all the questions I need to answer (data at bottom). This was a titration lab where a saturated solution of borax was prepared by adding 25.0 g of borax to 50 mL of distilled water. We used two different temperatures by using a hot plate to heat the solution. After the solid settled, we took 5.0 mL of the decant on top and put it into a graduated cylinder. After this we titrated it with 100 mL of HCl:

Analysis

A1. Determine the concentration of the dissolved B₄O₅(OH)₄^2â in each sample titrated; show a complete calculation for beaker #1.

A2. Calculate K_sp for each borax solution.

A3. Prepare a graph of your results, plotting the two quantities x and y (as defined in the introduction). Label everything clearly! Draw a best fitted line.

A4. Using y=mx+b of your best fitted line, calculate DHÂ° and DSÂ° for this reaction. Make sure to keep track of units, especially for R, so that the units of DHÂ° and DSÂ° work out sensibly.

Post Lab Questions:

Q1) What would happen to experimental Ksp if the buret was contaminated with other acids?

Summary :

Solubility of borax (make sure to indicate the unit and condition) :

Ksp (one or many? What makes sense?) :

Include graph (site the page). Include all relevant information directly on the graph.

Experimental DHÂ° in kJ/mol :

Theoretical DHÂ° in kJ/mol :

Experimental DSÂ° in J/mol K :

Theoretical DSÂ° in J/mol K :

Trial	Initial Volume (mL)	Change in Volume (mL)	Final Volume (mL)	Temperature (^oC)	Volume decant (mL)
1	0.3	10.6	10.9	24.0	5.0
2	10.9	15.9	26.8	30.5	5.0

The solubility of PbCl₂ increases with an increase in temperature. Is the dissolution of PbCl₂ (s) in the water exothermic or endothermic process? Explain.