Question

CF₃CH₂ F (HFC-134a, MW = 102) has replaced chlorofluorocarbon compounds for use a refrigerants. HFC-134a is produced from trichloroethlyene (CCl₂=CHCl, MW = 131.5) by the following reactions:

CCl₂=CHCl + HF ---> CF₃CH₂Cl + HCl

CF₃CH₂Cl + HF ---> CF₃CH₂ F + HCl

In 1999, over 1.3 million metric tons of HFC-134a were produced and production is increasing at a rate of nearly 20% annually. Maufactuers sell HFC-134a for $6.50/kg. Assume that you are a chemist working for a company that sold 93 million kilograms of HFC-134a last year. (a) If the sysnthesis had a reaction yield of 54%, how much trichloroethylene was needed to produce the HFC-134a? (b) You have developed a new catalyst that improves the yield of the synthesis of HFC-134a from 54% to 67%. If the company uses the same mass of trichloroethylene for next year's production, how many kilograms of HFC-134a can the company produce, if they use your new process? (c) Assuming the selling price of HFC-134a does not change, how much more money will the company make next year because of your work? 1 metric ton = 1000 kg

What is tritration? What is the function of an indicator? What does it mean to standadize the NaOh solution? What does it mean to overshoot the endpoint? Define Molarity. Write the reaction to standarize the NaOH & to determine the concentration of H₂SO₄. Write the equation to determine the molarity of NaOH & H₂SO_4.

Answer 1

We need to look closely to the stoichiometrical relationship, 1 mole of trichloroethlyene will produce 1 mole of HFC-134a, this is looking at the 2 reactions like if they were 1 global reaction, if we put the 2 equations together we get:

CCl₂=CHCl + 2 HF ---> CF₃CH₂ F + 2 HCl

so we have 93 million kilograms of HFC, we need to divide this value by the molecular weight MW = 102

93 million kilograms / 102 g/ g mol = 0.911765 million of kilomoles

So theoretically if we had a 100% of yield we need 0.911765 million of kilomoles of trichloroethlyene but we only have 54% so we need to divide 0.911765 million of kilomoles by 0.54, if we do this we get = 1.6884 million of kilomoles of trichloroethlyene requiered to produce the HFC from the statement, now we only need to multiply this value by the molecular weight of the trichloroethlyene, 1.6884 million of kilomoles of trichloroethlyene * 131.5 g/gmol = 222.0316 millions of kilograms of trichloroethlyene required.

b) we take those 222.0316 millions of kilograms of trichloroethlyene which are 1.6884 million of kilomoles, multiply this by 0.67 to get 1.131 millions of kilomoles of HFC we can get which multiplied by the molecular weight of 102 we get 115.38 millions of kilograms of HFC we can achieve.

c) We need to make 2 calculations, the revenue they will get with the original catalyzer with 54% of yield 93 millions of kilograms of HFC * $6.5 / kg = $604.5 million of dollars

New catalyzer, we said in part B we would be able to produce 115.38 millions of kilograms of HFC so 115.38 millions of kilograms * $6.5 / kg = $750.02 million dollars

Difference = $750 million - $604 million = $145.52 millions, this is the money the company will stop loosing because of the actual yield. Company will be able to improve the revenue by $145.52 millions