Percentage yield
. A 3.56 g sample of calcium chloride was dissolved in water and reacted with an excess of sulfuric acid to form a precipitate of calcium sulfate. 2 The percentage yield of calcium sulfate was 83.4%. Calculate the mass of calcium sulfate formed. Give your answer to an appropriate number of significant figures. [3 marks]
Answer Moles of calcium chloride = 3.56 / 111.1 = 3.204 × 10–2 Moles of calcium sulfate = 3.204 × 10–2 × 83.4/100 = 2.672 × 10–2 Mass of calcium sulfate = 2.672 × 10–2 × 136.2 = 3.6398 = 3.64 (g)
I understand the first bit but don't understand why you divide the %yeikd by 100 and times if by moles
Answer Moles of calcium chloride = 3.56 / 111.1 = 3.204 × 10–2 Moles of calcium sulfate = 3.204 × 10–2 × 83.4/100 = 2.672 × 10–2 Mass of calcium sulfate = 2.672 × 10–2 × 136.2 = 3.6398 = 3.64 (g)
I understand the first bit but don't understand why you divide the %yeikd by 100 and times if by moles
Original post by Groves1999
. A 3.56 g sample of calcium chloride was dissolved in water and reacted with an excess of sulfuric acid to form a precipitate of calcium sulfate. 2 The percentage yield of calcium sulfate was 83.4%. Calculate the mass of calcium sulfate formed. Give your answer to an appropriate number of significant figures. [3 marks]
Answer Moles of calcium chloride = 3.56 / 111.1 = 3.204 × 10–2 Moles of calcium sulfate = 3.204 × 10–2 × 83.4/100 = 2.672 × 10–2 Mass of calcium sulfate = 2.672 × 10–2 × 136.2 = 3.6398 = 3.64 (g)
I understand the first bit but don't understand why you divide the %yeikd by 100 and times if by moles
Answer Moles of calcium chloride = 3.56 / 111.1 = 3.204 × 10–2 Moles of calcium sulfate = 3.204 × 10–2 × 83.4/100 = 2.672 × 10–2 Mass of calcium sulfate = 2.672 × 10–2 × 136.2 = 3.6398 = 3.64 (g)
I understand the first bit but don't understand why you divide the %yeikd by 100 and times if by moles
Because in a perfect world with 100% yield, and with a 1:1 mol ratio, you would get an equal number of miles of the product as the original thing, however you only get a yield of 83.4% so you have to multiply the number of miles by that as the rest is not there.
For example, if For every £10 I put in I get £15 back, then my yield, which is the amount of extra money / original amount, would be 50% (5/10) * 100. My gain in this case is £5
So if I put in £20 then I would gain 0.5 * 20, which is £10.
I know I've introduced gain which is not the same as in this example but it's just to show you how multiplying by a ratio works.
how's this thread not locked yet?
thanks though, even if this question was made when youtube rewind was at 2018
thanks though, even if this question was made when youtube rewind was at 2018
(edited 10 months ago)
Quick Reply
Related discussions
- Chemistry question need help
- Amount of substance chemistry
- Chemistry help! (Amount of substances A - level OCR)
- Chemistry - yields question
- Chem yield help
- 5.1 Synthesis of a haloalkane PAG
- Chemistry A-LEVEL percentage atom economy HELP
- chemistry percentage yield questions aqa alevel
- OCR A Chemistry Pag 6.1 Synthesis of Aspirin
- When calculating atom economy do you include moles?
- Chem Multiple choice % yield Q!
- ethyl ethanoate comparison between lab and industry manufacture
- percentage yield questions
- Spec
- IGCSE Edexcel regional biology paper 2 (1B10/2HR) 7th june
- Igcse edexcel biology
- Edexcel igcse biology 1B
- iGCSE Edexcel Biology 10th May
- Do I need to be good at math to get in either real estate or trading
- iGCSE Edexcel Biology Paper 1BR 2024
Latest
Trending
Last reply 3 weeks ago
Determining how the temperature affects the pH of milk using titrationLast reply 4 weeks ago
How can I use 3D model kit to support my learning in A-level chemistry?
