Welcome Guest Search | Active Topics |

Tag as favorite
AAMC QPack Chemistry
Moiz_6047
#1 Posted : Wednesday, July 21, 2021 2:49:39 AM
Rank: Advanced Member

Groups: Registered
Joined: 5/3/2021
Posts: 35

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
Q6) Can you please explain what an ebulliator does, as well as, the function of a boiling chip? I don't believe we covered this in our notes.

Q8) Quick question here, but is + and - the same thing as R and S respectively? If they say something is + which direction is polarized light rotated?

Q11) Why would Na+ not react with water to form NaOH?



INSTR_Katrina_128
#2 Posted : Wednesday, July 21, 2021 5:16:53 PM
Rank: Advanced Member

Groups: Registered
Joined: 5/18/2021
Posts: 60

Thanks: 0 times
Was thanked: 0 time(s) in 0 post(s)
Hi Moiz,

Q6: An ebulliator is used to prevent superheating. What is superheating? Well, glassware that is used is typically very smooth (which is a good thing!). However, when you heat up a substance to boil it, it needs a place to start forming vapour bubbles. In a very smooth container, this is difficult. So, sometimes, the substance can OVERHEAT (above the boiling point) without actually becoming a vapour! We add in an ebulliator as a "non-smooth" substance so that the thing that we are trying to boil has something to latch onto when it wants to boil at its real boiling point. This prevents overheating and splashing at excess temperatures (called "bumping").

You may have encountered this in an undergrad lab. I remember using boiling chips when performing this exact lab in my first year in undergrad gen chem. ‚Äč

Boiling chips: https://orgchemboulder.c...Images/Boilingchips.jpg

Q8: No, R and S are NOT the same thing as + and -.

+ and - DO tell us which way polarized light is rotated.

+ rotates to the right (clockwise) and - rotates to the left (counterclockwise).

Which way a particular enanotiomer rotates and by how much MUST BE DETERMINED experimentally!

However, let's say that (R)-molecule rotates 38° to the left, then (S)-molecule will rotate 38° to the right.

Q11: In water, sodium hydroxide dissociates into Na+ and OH- ions because NaOH is a strong base. NaOH doesn't exist as a bonded NaOH molecule in water, but instead as dissociated ions.

Users browsing this topic
Guest
Tag as favorite
You cannot post new topics in this forum.
You cannot reply to topics in this forum.
You cannot delete your posts in this forum.
You cannot edit your posts in this forum.
You cannot create polls in this forum.
You cannot vote in polls in this forum.

Clean Slate theme by Jaben Cargman (Tiny Gecko)
Powered by YAF | YAF © 2003-2009, Yet Another Forum.NET
This page was generated in 0.101 seconds.