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# Percentage yield/Actual yield help? watch

1. 1) TiS + H2O => H2S + TiO
What is my percentage yield of titanium (ii) oxide if i start with 20 grams of titanium (ii) sulfide and my actual yield of titanium (ii) oxide is 22 grams?

[Mr of TiS = 80 and Mr of TiO = 63.9]
[Mass/Mr = 20/80 = 0.25 moles]
[0.25 moles of TiS => 0.25 moles of TiO]
[Moles x Mr = 0.25 x 63.9 = 15.98 grams]
[Actual yield/Theoretical yield = (22/15.98) x 100 = 137.67%]
[This is my working out but because i come out with a percentage yield of 137% i don't think it is correct]

2) U + 3 Br2 => UBr6
What is my actual yield of uranium hexabromide if i start with 100 grams of uranium and get a percentage yield of 83%?

[Mr of U = 238 and Mr of UBr6 = 717.4]
[Mass/Mr = 100/238 = 0.42 moles]
[0.42 moles of U => 0.42 moles of UBr6]
[Moles x Mr = 0.42 x 717.4 = 301.43 grams]
[(301.43/100) x 83 = 249.83 grams]
[Again this is my working out but because i get an actual yield much larger than 100 grams i am not sure if this is correct either]

Thanks.
2. (Original post by dhillon1)
1) TiS + H2O => H2S + TiO
What is my percentage yield of titanium (ii) oxide if i start with 20 grams of titanium (ii) sulfide and my actual yield of titanium (ii) oxide is 22 grams?

[Mr of TiS = 80 and Mr of TiO = 63.9]
[Mass/Mr = 20/80 = 0.25 moles]
[0.25 moles of TiS => 0.25 moles of TiO]
[Moles x Mr = 0.25 x 63.9 = 15.98 grams]
[Actual yield/Theoretical yield = (22/15.98) x 100 = 137.67%]
[This is my working out but because i come out with a percentage yield of 137% i don't think it is correct]

2) U + 3 Br2 => UBr6
What is my actual yield of uranium hexabromide if i start with 100 grams of uranium and get a percentage yield of 83%?

[Mr of U = 238 and Mr of UBr6 = 717.4]
[Mass/Mr = 100/238 = 0.42 moles]
[0.42 moles of U => 0.42 moles of UBr6]
[Moles x Mr = 0.42 x 717.4 = 301.43 grams]
[(301.43/100) x 83 = 249.83 grams]
[Again this is my working out but because i get an actual yield much larger than 100 grams i am not sure if this is correct either]

Thanks.
The second one is plausible since 100 g is that of uranium, and you actually expect to get 250 g of UBr6. so 250 / 300 is about 5/6 which is slightly more than 4/5(80%), so your percentage yield would be slightly above this, 83 %, as told. so it seems alright by me.

The first one however seems wrong. Your working is perfectly sensible.
3. (Original post by shengoc)
The second one is plausible since 100 g is that of uranium, and you actually expect to get 250 g of UBr6. so 250 / 300 is about 5/6 which is slightly more than 4/5(80%), so your percentage yield would be slightly above this, 83 %, as told. so it seems alright by me.

The first one however seems wrong. Your working is perfectly sensible.
Yeah turns out it was 137% but it was a stupid trick question designed to see if students can recognize 100% is the highest yield possible, god knows who thought of that question lol.

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