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# Chemistry questions help watch

1. Ethanol has a density of 0.789g/cm^3.

1.How many moles of ethanol did you use? (2cm^3 of ethanol was used).

2. From the equation, work out how many moles of ethanal could you produce if all the ethanol is oxidised to ethanal?

3. What volume would this occupy if its density is 0.784g/cm^3.

4. If you collected 5cm^3 of distillate, what proportion could be ethanal (assuming 100% product made)?

5. What do you think was the remainder of the distillate? (Think of its boiling point: 88'C)
3. (Original post by Zxr_)
Ethanol has a density of 0.789g/cm^3.

1.How many moles of ethanol did you use? (2cm^3 of ethanol was used).
So if 1 cm3 of ethanol weighs 0.789 g, then how much would 2 cm3 weigh?
Then once you know the mass used, you can use the formula
number of moles (n) = mass of compound (m) / molecular mass of compound (Mr)
4. (Original post by Zxr_)
2. From the equation, work out how many moles of ethanal could you produce if all the ethanol is oxidised to ethanal?)
Now if this the equation of ethanol to ethanal, with [O] just meaning that it's oxidised
Spoiler:
Show
You can see that 1 molecule of ethanol oxidises to form 1 molecule of ethanal, meaning that the number of moles of ethanol you had is the same as the number as the number of moles you will get for ethanal. Does that make sense?

3. What volume would this occupy if its density is 0.784g/cm^3.
So if you know the number of moles you should have of ethanal, and you also know the molecular mass of ethanal you can work out the mass of ethanal produced using the same n=m/Mr formula rearranged.
Then using the density formula,
Spoiler:
Show
you have the mass of the ethanal, and know the density and want to know the volume produced so plug those numbers in.
5. 4. If you collected 5cm^3 of distillate, what proportion could be ethanal (assuming 100% product made)?
So from the volume calculated in Q3, you can work out a percentage of what amount of the distillate is ethanal by doing the amount of ethanal divided by the total amount of distillate multiplied by 100.

5. What do you think was the remainder of the distillate? (Think of its boiling point: 88'C)
So now you know from Q4 that not all of the distillate is ethanal. Thinking back to the equation of this reaction what else is made in this oxidation process?
6. Thank you so much for your help- really appreciate it
7. (Original post by Zxr_)
Thank you so much for your help- really appreciate it
No problem!

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