[Jordon-H]

Hi,

Having problems calculating a theoretical yield -

C4H10O (12.5ml) + HBr --------- C4H9Br + H20

Any Help Would Kindly Accepted.

[TheUnassuming]

Start by calculating how many mols of starting material you began with.

[Jordon-H]

Basically,

1 mole of C4H10O gives you 1 mole of C4H9Br

[Babcock_Hall]

Welcome to the forum; I suggest you read through the forum rules, so that you can better understand its purpose.  You must take into account that commercial hydrobromic acid is a water solution of HBr, not a pure substance.  A good next step would be to show us the work you have already done.

[Jordon-H]

C4H10O (12.5ml) + HBr  C4H9Br + H20

In a 250ml flask you place 18g of sodium bromide and 20ml of water and add 12.5ml of butan-1-ol (density = 0.81gcm^-1)

[discodermolide]

So where does the acid come from?

[Jordon-H]

The Acid is formed as a byreaction in the experiment, hense why we dont need to add any.

many thanks

[Jordon-H]

but we do add 18molar sulphuric acid after preparing the 250ml flask

regards

[discodermolide]

Ok, so there is acid present throughout.
Anyway this is irrelevant for the yield calculation.
You have your reaction equation: 1 mole starting material goes to 1 mole product.
You have the density of butan-1-ol and the amount in mL. Therefore you can work out how many grams this is equivalent to, hence you know how many moles butan-1-ol you used. Consequently you now know the theoretical yield.

[Jordon-H]

I still dont know the calculations I have to do get my theoretical yield?

how many grams?

regards

[discodermolide]

The density of a substance is given in grams/mL, the density of butanol is 0.81 g/mL and you used 12.5 mL.
From this you can calculate the weight of butanol and hence the number of moles used.
You know that from the reaction equation 1 mole butanol gives 1 mole butylbromide
So you should now be able to do the simple calculation to get the theoretical yield in grams corresponding to the amounts you used.

[Jordon-H]

what is the simple calculation?

[discodermolide]

All the information you need is posted above. I will not be doing the simple calculation for you.
Perhaps someone else can explain this better than I?

[Jordon-H]

12.5ml/0.81x74.122= 0.136g/mole ?

[sjb]

12.5ml/0.81x74.122= 0.136g/mole ?

Not quite. What are all the units?