Minor questions about this topic (1 Viewer)

[xx06]

For the fermentation prac:
1.what is the conical flask with the rubber stopper properly called
2.Why was a 30'C water bath required?

For the 'preparing a standard solution' prac
1. Why must the burette and pipette be thouroughly rinsed with the solution to be used in them?

 

[punk_tartan]

For the fermentation prac:
1.what is the conical flask with the rubber stopper properly called
2.Why was a 30'C water bath required?

For the 'preparing a standard solution' prac
1. Why must the burette and pipette be thouroughly rinsed with the solution to be used in them?

to naswer your questions:

1. i always called it the ruber stopper,

2. the 30 degree waterath is required because this is the optimum tempertaure to allow the yeast to catalyse the reaction. yeast is an enzyme and hence it has a optimum temp for the rest rate of reaction to occur

STandard soloution:
1. the burette must be rinsed with what is in it so the molarity is not altered. Same for the conical flask. when mising a standard soloution, you need to know the molarity with great accuracy. If you have your conical flask rinsed with water, it can potneially atlter this molarity and thus you will not have an accurate molarity to calucualte for you unknown soloution in the burette.

hope this helps

 

[xx06]

30'c- yeah thats what i thought but how though, the water bath holds the limewater testube?

and wait does the limewater turn milky? sorri i missed the prac

 

[rama_v]

For the fermentation prac:
1.what is the conical flask with the rubber stopper properly called

For the 'preparing a standard solution' prac
1. Why must the burette and pipette be thouroughly rinsed with the solution to be used in them?

I suppose you could call it a reaction flask. Its up to you.

The burette and pippette must be thoroughly rinsed with the solution to be used in them or else this would change the number of moles of solution you are measuring out.

 

[passion89]

and wait does the limewater turn milky? sorri i missed the prac

Yes the limewater is supposed to turn milky because carbon dioxide is being released from fermentation reaction. It goes into the test tube with the limewater and theoretically when carbon dioxide reacts with limewater (calcium hydroxide), it turnrs cloudy/milky.

 

[s2indie]

1.what is the conical flask with the rubber stopper properly called

I think i called it the "conical flask with side arm", at least I think I'm thinking of the right experiment. i THINK.

 

[rama_v]

Yeah its sometimes called a side-arm flask. If you want the reaction of CO₂ with limewater, its actually:

Ca(OH)₂(aq) + CO₂(g) -> CaCO₃(s) + H₂O(aq)

 

[xx06]

What about the 30'c water bath. i guess the optimal conditions of ideally 30'c can't really suffice as the reason right? I thought it wouldn't because the waterbath holds the limewater testube.

 

[punk_tartan]

What about the 30'c water bath. i guess the optimal conditions of ideally 30'c can't really suffice as the reason right? I thought it wouldn't because the waterbath holds the limewater testube.

when we set up this experiment, we had a water bath around the reaction vessel not the limewater tube, as it would do no good having it around here, as it would only force the carbon dioxide out of souloutuion
henece, the water baths i need to have mmaximum temperature for yeast production

 

[Riviet]

A better word to use than maximum, would be the "optimal" temperature for the production of the yeast to take place.

 

[xx06]

Some more questions

1.Could sum1 plz do the eqn for the alkenes/alkanes prac- with cyclohexene and cyclohexane.
2.Explain why it is difficult to perform the hydration of ethene in the lab.
3.Explain why it would be unwise to attempt the hydratiohn of cyclohexene as an example of an alkene in the school labarotory.
4. Write an eqn for the hydration of cyclohexene
5.Why is a catalyst needed in the hydration of alkenes?
6. Name a catalyst and give evidence that it is acting as a catalyst?

Cheers matie

 

[vern]

Alkenes need a catalyst? I thought it was alkanes that do because alkenes have the double bond that is the reason they're so reactive