INTRODUCTION The relationship between free energy (Δ G), enthalpy (Δ H), entropy (Δ S) and the equilibrium constant (K) for a chemical reaction at a specific temperature (T), is shown in equation (1) below. The ?H value was found to be 29.46 kJ mol-1, and ?S was found as 0.120 kJ mol-1. Here, ?H is assumed to be constant over the temperature range of the experiment, and ?S represents the average change in entropy. Borax (sodium tetraboratedecahydrate), a mineral found in dry lakebeds in California, is used as a preservative and in the manufacturing of soap and glass. Problem 21 What are three different methods to calculate $\Delta G^{\circ}$ for a reaction? ENTHALPY AND ENTROPY OF BORAX DISSOLUTION REPORT INSTRUCTIONS Format your ELN as you did in week 2 for the rest of the experiments in Chem 1LC and 1LD.

and ln K sp for each of the points graphed in part A.

In part B, the Nernst Equation will be verified by measuring cell potential as a function of the ion conc. Make a new graph with ln K sp on the vertical axis and 1/T (K-1) on the horizontal axis. Determination of K sp, ΔG 0, ΔH 0, and ΔS 0 for the Dissolution of Calcium Hydroxide in Water: A General Chemistry Experiment William B. Euler , WEULER@CHM.URI.EDU, (401) 874-5090

D S univ = D S sys + D S surr. From the slope of your graph calculate Ho, the heat of …

Determine the slope of the best-fit line through the experimental data. Total entropy change, also called the entropy change of the universe, is the sum of the entropy change of a system and of its surroundings:. To calculate entropy, Δ S, plug the value just found for Δ H into equation (2) and solve using a data point.

Sample calculations - calculations of your data alone for all of the items listed above Graph lnK vs 1/T Show a trendline and provide the R2 value Determine ΔH (kJ/mol) and ΔS (J/mol K) from the graph SHOW HOW YOU DO THIS!! The state enthalpy and entropy were determined by plotting Ln(K sp) with respect to 1/T (Figure 1). in on e of the half cell rxns. Calculate the Ksp of each Borax solution at the various temperatures. To calculate the standard cell potential and confirm the observed activity series for common metals through construction of simple electrochemical cells.

A plot of ln K versus (1/T) should result in a straight line with a slope equal to (– Δ H°/R) and a y-axis intercept equal to (Δ S°/R).

How can you calculate the standard entropy change for a reaction from tables of standard entropies?

The Equilibrium constant K sp In order to construct a graph of ln K versus 1/T, we will need the values of T (temperature) and K Use the linear curve fit option in excel to obtain the best fit linear fit.

Enthalpy, Δ H, is determined from the slope.

The direction of spontaneous change is the direction in which total entropy increases. The relationship between ln K and 1/T is valid only if ΔH° and ΔS° are not temperature-dependent quantities.

Which method would you choose to calculate $\Delta G^{\circ}$ for a reaction at a temperature other than $25^{\circ} \mathrm{C}$ ?

Question: Question 8 How Do You Calculate The Entropy Of Borax Dissolution From In K Versus (1/T) Graph A From Enthalpy And Y-intercept O B. Enthalpy and Entropy of a Borax Solution ENTHALPY AND ENTROPY OF A BORAX SOLUTION The linear relationship modeled by the line of best fit corresponds to the expression: ( [Eqn 4] Where the enthalpy is was derived from the slope of the line and the entropy was determined from the corresponding y-intercept term, multiplied by the ideal gas constant (8.314 J/molK). Thermodynamics of the Dissolution of Borax ... calculations of your data alone for all of the items listed above Graph lnK vs 1/T Show a trendline and provide the R2 value Determine ΔH (kJ/mol) and ΔS (J/mol K) from the graph SHOW HOW YOU DO THIS!!

To determine H and S, make a plot of the experimental data on Excel using the equation developed in the introduction. last to calculate the formation of a Cu(NH3)4 aqua complex by adding NH3 to Cu/CU2+ half cell 3. 2.

Enthalpy and Entropy of a Borax Solution Revised 4/28/15 ENTHALPY AND ENTROPY OF A BORAX SOLUTION REPORT INSTRUCTIONS Format your ELN as you did in week 2 for the rest of the experiments in Chem 1LC and 1LD.

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ln(Ksp) was plotted versus 1/T to obtain the graph shown in Figure 1.