I’m really struggling on understanding how to do these conversions and I am hoping someone can help me understand it step by step. I have a midterm exam this week and I really want to grasp this concept. D: The question goes:
Wine is produced by the fermentation of grapes. In fermentation, the carbohydrate glucose (C6H12O6) is converted to ethanol (C2H6O) and carbon dioxide (CO2), according to the given balanced equation.
C6H12O6=2C2H6O+2CO2
How many grams of ethanol (C2H6O) are formed from 0.95 mol of glucose (C6H12O6)? Be sure your answer has the correct number of significant figures.
In: Chemistry
Chemical equations are written in moles – you can think of a mole as if it’s representing *one* molecule (although in reality it is representing a large but still very specific number of molecules).
So the equation here says that one mole of C6H12O6 becomes 2 moles of C2H6O and 2 moles of CO2
They give you moles to begin with, which is nice of them. You have 0.95 moles of C6H12O6, which becomes (0.95×2) or 1.9 moles of C2H6O. Now you just need to get grams.
Now the molar mass of C2H6O is 46.068 g/mol (googled it but you can find this yourself easily if your teacher requires it – if you need this explanation then let me know). 1.9 moles at 46.068 g/mol is 87.53 grams, at two sig figs that’s 88 grams.
Because this feels like doing your homework 😀 let me sketch out the steps…see if you can do it from this, and if you’re still jammed let us know.
1. The mole ratio we’re looking at is 1:2, because the reaction says one C6H12O6 turns into 2 C2H6Os. In other words, the amount of C2H6O will always be 2x the amount of glucose, so if we’re starting with 0.95mol of glucose, how much C2H6O will this reaction make? >!0.95 x 2 = 1.90mol of C2H6O!<
2. What’s the molar mass of C2H6O? >!2×12.01 + 6×1.01 + 16.00 = 46.08g/mol!<
3. Use m = nM to get the mass of C2H6O. >!1.90mol x 46.08g/mol = 87.552g of ethanol!<
4. Significant digits. >!0.95 has two sig digs, the molar mass had four and the mole ratio has “infinite sig digs”, so our answer can only have two; round to 88g.!<
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