Freon-12 is made by the Swarts reaction: CCl₄ + 2 HF → CCl₂F₂ + 2 HCl, with antimony trifluoride as…
Contributed by StemPy LabTry it on paper first. A hint, the key idea and the worked solution are here when you need them.
Freon-12 is made by the Swarts reaction: , with antimony trifluoride as the catalyst. A chemist starts with of tetrachloromethane. The molar masses are for , for HF and for . The yield is . One mole of gas occupies at standard temperature and pressure. Find the mass of hydrogen fluoride needed, the mass of freon-12 obtained, and the volume of the freon-12 gas at standard temperature and pressure.
Need a reminder? The key ideaShow
The percentage of an element in a compound is the mass of that element in one mole divided by the molar mass. Freons are made from tetrachloromethane and HF. DDT is made from two moles of chlorobenzene and one mole of chloral. One chlorine atom in the stratosphere destroys about ozone molecules.
The worked solution
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Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. Amount of CCl4. .
Step 2. Hydrogen fluoride. , which is .
Step 3. Freon-12. At full yield . At : .
Step 4. Volume. .
Answer: of HF, of freon-12 and of gas.
Check. Mass of the reactants for full yield: . The products are of freon-12 and of HCl, which also add to .
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