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A 1.536 sample of K2SO4 is dissolved in 20.0 g of water (Kf = -1.86oC/m)). The solution freezes at -2.07oC. What is the van’t Hoff factor, i, for this solution?

Calculate the volume of 0.500M stock of Fe3+solution you need to dilute with deionized water to prepare 80.0 mL of 0.0750M solution of Fe3+(aq).

Which substance would lower the freezing point of a solvent the most? 

In the calorimeter experiment that explores the combustion of a fuel, which part of the equation stays constant? ΔH =ΔU + VΔp

Consider the endothermic reaction: N2O4(colorless gas) 2 NO2(brown gas). Why does the color get paler after the pressure increases? 

The Haber process is exothermic. In which direction will the equilibrium be shifted by heating the reaction chamber with the bunsen burner? The reaction is: N2(g) + 3H2(g)  ⇌ 2NH3(g)

The van’t Hoff Equation is a mathematical relationship relating the equilibrium constant to the temperature of the system: lnKeq=-∆Horeaction/R(1/T) +∆Soreaction/R Where ΔHoreaction and ΔSoreaction are correspondently standard enthalpy and entropy changes of reaction and R is the universal gas constant (8.314 J mol-1k-1).  The graphical interpretation of van’t Hoff Equation in form of the plot of lnKeq vs 1/T gives you an opportunity to determine both thermodynamic functions from the value of the equilibrium constant: the slope of this plot is equal to -ΔHoreaction/R and y-intercept – to ΔSoreaction/R.  Note that your values will come in Joules and the temperature for all thermodynamics calculations should be converted to Kelvins. The student explored the famous Haber process: N2(g) + 3H2(g)  => 2NH3(g), and obtained the following data for the equilibrium constant: Temperature, oC Equilibrium constant 25.00 3.86E+05 75.00 2.27E+03 125.0 4.04E+01 175.0 1.52E+00 225.0 8.37E-02 Assignment and Rubric: Use your Lab Report Template to answer the questions below. Follow all instructions to get full credit. Please answer the following questions:  Make the necessary calculations and build the data table lnKeq vs 1/T   Generate a graph of ln Keq – 1/T and report the trendline equation (5 pts) and R2. (1 pts) Using the slope calculate the enthalpy change, show your work, include, and report correct units. (3 pts) Using the y-intercept calculate the entropy change, show your work, include, and report correct units. ( 3pts) Assuming the accepted value for the standard enthalpy change at 500K to be -99.88 kJ, calculate the % error of the experiment? and explain the source of the error. (1pts) Embed your calculations to the Exam Calculations for 4 pts after you submitted this exam Results:trendline equation: R2: ΔH: ΔS: %Error:      

For the burning of a liquid fossil fuel the values of thermodynamic functions will be:  

What is the concentration of the following compound as measured in a 1 cm cuvette: Molar absorptivity: 4525/M*cm. Absorption: 0.6358 Attention: SigFig  

A 1.436 sample of MgSO4 is dissolved in 20.0 g of water (Kf = -1.86oC/m). The solution freezes at -1.57oC. What is the van’t Hoff factor, i, for this solution?