Percent yield problem of Chemistry
When 20.0 L of fluorine gas at STP is slowly bubbled throught 100.0g of liquid boron triiodide, 7.55 g of boron trifluoride is produced. What is the percent yield?
- 魏王將張遼Lv 71 十年前最愛解答
First of all, let's see the equation for the reaction:
3F2 + 2BI3 → 2BF3 + 3I2
From the equation, we can see that 3 moles of fluorine gas react with 2 moles of boron triiodied to give 2 moles of boron trifluoride.
Then, number of moles of fluorine gas present = 20/22.4 = 0.893 moles
Number of moles of boron triiodide present = 100/(10.8 + 3 × 127) = 0.255 moles
Therefore, we can see that boron triiodide is now the limiting reactant in which 0.255 × (3/2) = 0.383 moles of fluorine gas has been reacted.
Hence, from the above deductions, we can see that 0.255 moles of boron trifluoride can be produced theoretically.
Now, number of moles of boron trifluoride produced = 7.55/(10.8 + 3 × 19) = 0.111 moles.
Therefore the percentage yield of boron trifluoride is:
0.111/0.255 × 100% = 43.6%資料來源： My chemical knowledge