Need Help On A2 Chemistry Coursework

[Guest _singh_]

noworriesbro. what u studying?

[I humbly bow]

Pyareo Jee, I am doing A2 Chemistry this year and I am really bad at doing courswork. So i have come to guru jee's sangat for help on my chemistry coursework and I am really badly stuck.

This courswork is the Hydrolyse of ester methyl benzoate to prepare benzoic acid, C6H5COOH.

C6H5COOCH3 + OH- ------> C6H5COO- + H20

C6H5COO- + H+ -----> C6H5COOH

Could the sangat who do chemistry or who have done this courswork tell me all the observations.

Please I wouldreally appreciate this help from my gursikh brothers and sisters.

Ive just graduated in Chemistry, so i should know this lol

What do you mean by observations? Are you talking colour changes? pH? what solvent have they told you it's performed in? send me the actual question they've asked you, i'll have a look at it!

[Guest :S Confused :S]

Im struggling at AS chemistry - i have no idea what or how to work out moles!

[Guest _singh_]

Pyareo Jee, I am doing A2 Chemistry this year and I am really bad at doing courswork. So i have come to guru jee's sangat for help on my chemistry coursework and I am really badly stuck.

This courswork is the Hydrolyse of ester methyl benzoate to prepare benzoic acid, C6H5COOH.

C6H5COOCH3 + OH- ------> C6H5COO- + H20

C6H5COO- + H+ -----> C6H5COOH

Could the sangat who do chemistry or who have done this courswork tell me all the observations.

Please I wouldreally appreciate this help from my gursikh brothers and sisters.

Ive just graduated in Chemistry, so i should know this lol

What do you mean by observations? Are you talking colour changes? pH? what solvent have they told you it's performed in? send me the actual question they've asked you, i'll have a look at it!

Thank you "I humbly bow" it shows gursikhs are willing to help when one needs it. Thanks a lot.

[Guest _Singh_]

For this excersie you are given full intructions for the practiacal procedure andthese must be followed exactly. it is however up to you to consider suitable safety precautions and toorganise your time appropriately . You should carefully consider what is the most effective way of handling the materials and apparatuss in order to obtain the best results.

Hydrolyisis of an ester

In this experiment, you will hydrolysis the ester methly benzoate to prepare benxoic acid C6H5COOH.

C6H5C00CH3 + OH- ----> C6H5COO- +H2O

C6H5COO- + H+ ---> C6H5COOH

You must provide writtten evidence that you have given careful consideration about the hazards of the chemicals used in the context of this experiment.

At each stage of the hydrolysis you should record clearly all observations and any measurements taken.

I think it would be colour changes and what you see. This is because we did'nt use universal indicators to find out the ph.

We also did recrystalising in the experiment.

If you want I can also send you the procedure.

Thanks a lot it shows gurikhs are always willing to help.

[I humbly bow]

For this excersie you are given full intructions for the practiacal procedure andthese must be followed exactly. it is however up to you to consider suitable safety precautions and toorganise your time appropriately . You should carefully consider what is the most effective way of handling the materials and apparatuss in order to obtain the best results.

Hydrolyisis of an ester

In this experiment, you will hydrolysis the ester methly benzoate to prepare benxoic acid C6H5COOH.

C6H5C00CH3 + OH- ----> C6H5COO- +H2O

C6H5COO- + H+ ---> C6H5COOH

You must provide writtten evidence that you have given careful consideration about the hazards of the chemicals used in the context of this experiment.

At each stage of the hydrolysis you should record clearly all observations and any measurements taken.

I think it would be colour changes and what you see. This is because we did'nt use universal indicators to find out the ph.

We also did recrystalising in the experiment.

If you want I can also send you the procedure.

Thanks a lot it shows gurikhs are always willing to help.

thats cool lol,

yeah send me the procedure please, have you actually done this experiement yet or is the coursework the planning?

for hazards google the chemical name and click on a site that sells it; they have to give you all the hazard info e.g.

methyl benzoate - HARMFUL IF SWALLOWED OR INHALED. CAUSES IRRITATION TO EYES AND SKIN. COMBUSTIBLE LIQUID AND VAPOR.

Lab Protective Equip: GOGGLES; LAB COAT; VENT HOOD; PROPER GLOVES; CLASS B EXTINGUISHER

[I humbly bow]

Im struggling at AS chemistry - i have no idea what or how to work out moles!

moles are easy! post a question your stuck on, i'll go through it with you :-)

[Guest _singh_]

i have done it but never wrote the observations down. i will send u the procedure please helpme thanks.

[I humbly bow]

i have done it but never wrote the observations down. i will send u the procedure please helpme thanks.

FORGOT to take observations! Where’s my jooti?!

I’ll bail you out this time, but next time make notes on everything that happens when you do an experiment OK!

All I needed to know from the procedure is what solvent your using as the OH donor.

I think in coll you’d be using water (really slow reaction) or sodium hydroxide (much faster than water)

Well both are colourless so the observations will be the same.

Methyl benzoate is an colourless organic species and it doesn’t mix well with aqueous stuff like H20 and NaOH, so we say that NaOH and methyl benzoate are immiscible. So basically if you add the two chemicals to a flask they will separate and form 2 layers. They react at the site where they meet.

Actually even if you took observations this is hard to see! Because there both colourless. But since methyl benzoate is less dense that NaOH/water it will sit on top as the organic layer. The water/NaOH will be underneath – the aqueous layer. It should look kinda like a clear oil layer on top of clear water.

You’d probably do this reaction under reflux, heat with a stirring bead to get them to mix and react, but again I don’t have your procedure. Anyway while it’s refluxing you’ll get droplets of stuff that looks like oil on the side of the flask, when these are all gone and the mixture stops separating, the reaction is complete. Should still be a colourless liquid at this stage. This is the saponification stage.

Then you need something that will make the benzoic acid crystallise out, so obviously a acid like HCl or H2SO4 im sure you probably used one of them in this expt. This will give you crude benzoic acid.

Ive only ever used benzoic acid as a liquid so I don’t know what it looks like as a solid, but as a rule of thumb generally a colourless liquid is a white powder. But this is crude so I’d say that it would have been a cream or off-white solid due to impurities,

Then you did recrystallisation yeah, so it should be a white powder if you did the recrystallisation really well (unlikely at coll), or a whiter powder than it was before the recrystallisation (more likely to have happened).

That should help, I’ve got a busy week at work next week, so if you don’t understand any of it, you might have to wait a while for a reply. Remember to include diagram equations as well as the worded equations in your report.

[iaana]

man this is wickied!!!!! first time i seen this on sikhsangat (not that im on here much).. but im doing chem and bio A2.. mannn im realy worried i need to clock it this year... aplying for pharmacy this year.. and i only got CCC last year meaning im soooooooooo guna have to pull ma socks up.. any chance i could get ur add just encase i need some help too :WW: thanx bro