This question is about an experiment to investigate the effect of temperature on the equilibrium constant, $$\(K_{1}\)$$, of the reaction shown. $$\[ \mathrm{Fe}^{3+}(\mathrm{aq})+\mathrm{SCN}^{-}(\mathrm{aq}) \rightleftharpoons \mathrm{FeSCN}^{2+}(\mathrm{aq}) \]$$ The data collected is used to determine the value of the enthalpy change of the reaction. To set up the equilibrium, aqueous iron(III) nitrate, $$\(\mathrm{Fe}\left(\mathrm{NO}_{3}\right)_{3}(\mathrm{aq})\)$$, is mixed with aqueous potassium thiocyanate, $$\(\mathrm{KSCN}(\mathrm{aq})\)$$. Aqueous iron thiocyanate ions, $$\(\operatorname{FeSCN}^{2+}(\mathrm{aq})\)$$, have a red colour. A colorimeter is used to measure the absorbance of the reaction mixture. A calibration graph can then be used to determine the concentration of $$\(\mathrm{FeSCN}^{2+}(\mathrm{aq})\)$$ in the reaction mixture. Table 2.1 shows the solutions for the experiments. A student obtains the results given in Table 2.2. (i) Use the calibration graph in Fig. 2.1 to complete column 3 in Table 2.2. Record values to one decimal place. (ii) Use equation 1 to complete column 4 in Table 2.2. Record values to the nearest whole number.

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