the centCT of maxs. The thrre 10a, does the center of (a) move to the 25 m) in Figure 8.10a, find the CATING YOUR LAB PARTNER'S linares of the a person's center of gravity. Suppose your lab par height Lof 173 cm (5 ft, 8 in.) and a weight wof- You can determine the position of his c having him stretch out on a uniform end by a scale, as shown in Figur w, is 49 N and the scale read tance of your lab partr of the board. e to find a center of gravity. EM In this example we show how to find the le 5. STRAT 133 General Chemistry II Laboratory Manual, 2019 Revision Determination of Some Thermodynamic Data for the Dissolution of Borax .e: 1) Why is methyl orange used as the indicator for the endpoint of the titration in this lab? Nan asasmng acrd. In numn of a shong Brange acra and weak boie The equiuulence pornt changy at on me aird srde of 7.mety! abozt2u Tetruborate m is a weaekK base , and HA 2) What is the Ksp for lithium tetraborate if 50.0 mL of a saturated solution of lithium tetraborate requires 12.11 mL of 0.500 M HCl to titrate the tetraborate ion? ull be ndnamg agood opmon. 3) Based on the Ksp you calculated in the previous question, what is AG° for the dissolution of lithium tetraborate at 25°C? APPAPPPPP hasses on the lefl and right in i f mass 2.00 kg is placed at (0, 0.25 m) i directions thie't har endent ot the other two cE - 0.0385 m PROBI LE 8.4 Use te zuons ouree anu General Chemistry II Laboratory Manual, 2019 Revision 131 Determination of Some Thermodynamic Data for the Dissolution of Borax CENTER Background: Borax, or sodium tetraborate (NazB4Os(OH)4), is used in many laundry products to aid in the cleaning of clothes. There are even some commercial products that are exclusively borax on the market which are sold as laundry aids. Borax is water soluble, but its solubility varies markedly with temperature. At room temperature, borax is somewhat soluble. We can write the solubility equilibrium and the solubility product constant for borax as shown below. Example & hrough on to sO NazB4Os(OH)4(s) = 2Na*(aq) + B4Os(OH),²(aq) or Ksp = [Na*] [B4Os(OH)4²] If we have a solution that is saturated with borax, the concentration of the tetraborate anion can be determined by titration with a solution of hydrochloric acid resulting in the formation of boric acid. 5.5 no B4O5(OH)4²- + 2H* + 3H2O →> 4H3BO3 Each mole of the tetraborate ion requires two moles of hydrochloric acid to react completely with it. If the concentration of the tetraborate ion is known, the concentration of sodium ion is equal to two times the concentration of the tetraborate; assuming that both ions in solution come only from the dissolution of borax. In this lab you will use the titration with HCl to determine the Ksp values for borax over a series of different temperatures. This data will then be used to determine different thermodynamic values for the dissolution reaction of borax. We have learned several equations that can be used to calculate the Gibbs' Free Energy (AG) for a reaction. nilyo berubstg blo oru din Aont s20T Dcchc yuar AG = AH- TAS AG = -RT(InK) %3D (8 tb bbA If we combine these two equations, we get: This equation can be rearranged to give: w booson al mlon noimloa biooo1 %3D AH – TAS = -RT(InK). bos ynine broout to zgibusn od hetac M Jan ΔΗ-ΤAS InK = -RT 81st which rearranges further to give: or InK = T0) CC AS -AH AS InK = ДН 1 RT R. 6. %3D RT R we will get a straight T. The boxed form of the equation suggests that if we determine the values of Ksp for borax -AH and whose intercept is AS over a series of temperatures and then make a plot of InKsp VS. R line whose slope is