The (OH ] of a solution can be determined from the pOH using the equation: (OH¯] = 10- POH Where: (OH ] = hydroxide ion concentration a Use the rules for logarithms and exponents to solve for pOH in terms of (OH ]. NOTE: Capitalization counts. pOH = Submit

1. An impure sample of compound A is contaminated with two impurities B and C. The sample is to be purified by recrystallization using ethanol as the solvent. The solubility properties of the three components are summarized below. Solubility in Solubility in ethanol Solubility in 50 mL Solubility in 50 mL ethanol at -78 °C at - 0°C ethanol at -78 °C ethanol at - 0°C (g) (g) Compound A 0.12 g/mL 0.02 g/mL Impurity B 0.58 g/mL 0.04 g/mL Impurity C 0.005 g/mL 0.0003 g/mL The impure (7.5 g) sample contains 5.0 g of compound A, 1.5 g of B and 1.0 g of C and is recrystallized using 50 mL of ethanol. The sample is boiled with 50 mL of ethanol, filtered by gravity and then cooled in ice and filtered by suction. a) How much compound A should be obtained as the final product? Will the sample be contaminated with any of the impurities? Explain (using calculations to support your answer-fill in the missing masses in the table above). Hint: For this question you should calculate the mass of each…

Consider the dissociation of methane to graphite (C) and hydrogen gas. For the methane at 298K, the data available are: k] -74.85- mol = -80.67- mol · K A,GEgraphite = A,G Calculate the equilibrium constant (K) of the dissociation of methane a. at 298 K with the appropriate units. b Assuming that A,H is independent of temperature, calculate the equilibrium constant (K) of methane dissociation at 1000 K. Calculate the ratio between the amounts of methane and hydrogen C. gases at 298 K and 0.2 barg.

Table Q4 shows the solubility of liquid trichlorohexane in toluene (also liquid) at equilibrium at different temperatures, where species 1 is trichlorohexane and species 2 is toluene. These data are obtained at 1 atm. X1 0.037 0.050 0.085 0.135 0.199 0.288 0.364 0.482 0.500 0.585 Table Q4 Temperature (°C) 92.18 100.00 107.11 111.96 113.84 112.87 109.63 101.91 100.00 90.05 (a) Plot a properly labeled T-x₁ diagram of this binary mixture at 1 atm. (b) Estimate the composition of each phase at 110°C for this binary mixture. (c) At 110°C and 1 atm, trichlorohexane is added dropwise into an initially pure toluene until the mole fraction of trichlorohexane reaches 0.5. Assuming equilibrium is preserved during every addition of trichlorohexane, describe what you would see if the whole process is conducted in a transparent beaker. (d) At 100°C, determine the A12 and A21 in the two-constant Margules equation. Justify any assumptions that you make.