Esters

[Chemistry!!]

1) Discuss the characteristic functional features found in the alohols and acids that is missing in the ester. Discuss how its presence or absence allows the reactants to dissolve well in water but limits the ability of the product to dissolve in water and therefore causes it to float on the cold water in the watch glass.

 

 

 

2) Esters are oten a key component of oils pesent in flowers. What purpose would the ester serve in flowers?

 

 

 

3) Why do flowers have less smellon rainy cool dyas ad why does the rain not wash the esters away? Why did weplce the ester on a cooled watch glass in the lab and not on your skin?

 

I have spend an hour researching these questions and have no clue. Can anyone help me?

[Suxamethonium]

Ok, so this probably should have been put in homework? But to help you out a bit think about these questions:

 

1) What are the functional groups of an alcohol, acid and ester? What do they look like? Which is most polar, which is least polar? Is water polar or non-polar? Following the principle "like dissolves like" which functional groups should be most soluble in water?

 

2) What do you know about esters that might be related to flowers? To be fair, I feel this question is vague and will depend on what was told to you in class.

 

3) In regards to the rain, think about question 1. You should also think about why COOL was specified (hint: it is not as required for large esters like cooking oil). As for the skin part- think about water and sunblock (oily kind) what happens when you try to rub them on your skin and how might this concept apply to esters?

 

Have a think, and post up your results and I'll help you more if you need it.

[Chemistry!!]

For question 1, alcohols have and OH functional group, so they have hydrogen bonding making it dissolve in water (has a high solubility). I don't know what acids have? Esters have an O double bond c single bond O. So it dosnt have hydrogen bonding so it wont dissolve in water. But what does it have to do with floating?

 

 

 

For 2, all i know is esters have an o double bnd c single bond o. So I don't know what that has to do with flowers?

 

 

 

For 3, all I know is that esters don't have hydrogen bonds so they arent very polar, meaning they wont dissolve in water very well, but what does tha have to do with the questions.

 

 

Thanks.

 

 

 

[Suxamethonium]

1) So, yes OH has hydrogen bonding. It can Accept and Donate hydrogen bonds. Acids have C=OOH. So Hydrogen band Accept and donate. Also acids can dissociate to give COO^- which is much more polar than hydrogen bonding alone.

 

Esters can Accept, but not donate hydrogen bonds. As such they have some polar characteristics but are not nearly as polar as acids and alcohols. Unlike the acid and alcohol, the ester is not polar enough to dissolve in the water solution and as such it separates as a non-polar layer. This layer can sink or float depending on the density of the ester compared to water.

 

2) Hint: Most esters have well-known smells.

 

3) Think about what you just said, and think about how you could use that to relate to the questions they asked. For example, do any of the questions refer to water in any way? Science is not just about knowing and understanding test data, but about extrapolating it and applying it to real-world situations.

[Chemistry!!]

1) So, yes OH has hydrogen bonding. It can Accept and Donate hydrogen bonds. Acids have C=OOH. So Hydrogen band Accept and donate. Also acids can dissociate to give COO^- which is much more polar than hydrogen bonding alone.

 

Esters can Accept, but not donate hydrogen bonds. As such they have some polar characteristics but are not nearly as polar as acids and alcohols. Unlike the acid and alcohol, the ester is not polar enough to dissolve in the water solution and as such it separates as a non-polar layer. This layer can sink or float depending on the density of the ester compared to water.

 

2) Hint: Most esters have well-known smells.

 

3) Think about what you just said, and think about how you could use that to relate to the questions they asked. For example, do any of the questions refer to water in any way? Science is not just about knowing and understanding test data, but about extrapolating it and applying it to real-world situations.

for 2 does it relate to bees?

 

 

 

and for 3 I'm still not sure, and it's due tomorrow.

 

 

 

also do you know the smell of octanol reacting with salicylic acid by any chance

 

 

 

thanks

 

and much help would be appreciated

[Suxamethonium]

It can relate to bees. Bees have receptors to detect certain chemicals (termed pheromones), a lot of them esters. We too can detect these esters as smell. Many esters smell pleasant, fruity or aromatic.

 

Octylsalicylate- not sure how it smells but it's used in sunscreen.

 

And for three- if esters are not very soluble will the rain wash them away? If it is a cold day will the esters be as volatile? What consequences does this have?