Urgent Chem Questions (1 Viewer)

[Validity]

1. how would you define an acid ? do i use the word DISSOCIATE OR IONIZE? completely/partially in solution to produce H+ ions? [solved]

2. In regards to condensation polymeization where a difunctional monomer is required, what does this actually mean? does it mean 2 DIFFERENT functional groups? could someone give me an example please [solved]

3. How does increasing the concentration of an acid make it a stronger acid? doesn't it only make it concentrated? [solved]

4. For the monomer of glucose, do we have to say D-glucose or can we say Beta- GLucose? [solved]

5. How do you convert cellulose to glucose? [solved]

6. Do we need to know about protonation for the indicators? such as HIn- etc.? [solved]

7. Why are micelles negatively charged?

8. What state is Sulfur in when it is combusted in the first step of the Contact Process? i thought the sulfur was sprayed into the chamber in molten form but i read answers which say solid form

 

[someth1ng]

1. how would you define an acid ? do i use the word DISSOCIATE OR IONIZE? completely/partially in solution to produce H+ ions?

2. In regards to condensation polymeization where a difunctional monomer is required, what does this actually mean? does it mean 2 DIFFERENT functional groups? could someone give me an example please

3. How does increasing the concentration of an acid make it a stronger acid? doesn't it only make it concentrated?

1. An acid is a proton donor and a base is a proton acceptor (Bronsted-Lowry). Strong acids ionise completely in solution while weak acids ionise partially in solution to produce H+ ions.
2. By difunctional, they mean, there are two sites reactive sites (usually two function groups) such as two hydroxyl groups that react in the condensation reaction of two glucose monomers - they can be the same or different.
3. Increasing concentration DOES NOT make it stronger. It only makes it more concentrated.

 

[Validity]

1. An acid is a proton donor and a base is a proton acceptor (Bronsted-Lowry). Strong acids ionise completely in solution while weak acids ionise partially in solution to produce H+ ions.

so for defining acids and bases, you wouldn't use the word dissociate?

 

[someth1ng]

so for defining acids and bases, you wouldn't use the word dissociate?

It's not an issue between ionise and dissociate into ions. Essentially, they mean the same thing.

 

[someth1ng]

4. For the monomer of glucose, do we have to say D-glucose or can we say Beta- GLucose?

5. How do you convert cellulose to glucose?

6. Do we need to know about protonation for the indicators? such as HIn- etc.?

It depends which monomer. For starch, it is alpha-glucose and for cellulose, it is beta-glucose.

Cellulose can be converted to glucose by hydrolysis.
Crushing the cellulose and adding dilute H2SO4 and heated - this hydrolyses the cellulose to produce glucose and then, the sulfuric acid is usually neutralised by CaCO3 or Ca(OH)2 to precipitate CaSO4. Then, it is filtered to remove any remaining residue. This should leave only glucose and water.

No, you don't need to know about protonation of indicators.

 

[study-freak]

so for defining acids and bases, you wouldn't use the word dissociate?

I would say:
- ionise for acid/base as that's actually what happens
- dissociate for NaCl(s) going into water and separating (dissociating) into Na+(aq) and Cl-(aq) ions - they are already ions to begin with

 

[Validity]

thanks, bump

 

[karnbmx]

Micelles are negatively charged because the negatively charged oxygen atoms from the polar water molecules (which themselves form ion-dipole forces with the charged end of the soap anion) stick out from the micelle and form its outer perimeter. Remember, this is what keeps them stable and stops the oil/soil from clumping together and reforming.

 

[nucgaek]

Micelles are negatively charged because the negatively charged oxygen atoms from the polar water molecules (which themselves form ion-dipole forces with the charged end of the soap anion) stick out from the micelle and form its outer perimeter. Remember, this is what keeps them stable and stops the oil/soil from clumping together and reforming.

What? The oxygen atoms from water don't have anything to do with a micelle.

A micelle is the oil or non-polar substance you're cleaning off, it has detergent/soap molecules embedded in it (due to non-polar tail), the heads are negatively charged for soaps and anionic detergents, which makes them negative? (Cationic detergents = postively charged micelle).

And you use liquid sulfur for S+O2 -> SO2

 

[7eleven]

7. Micelles are formed by sodium stearate molecules. And sodium stearate (aka soap) dissasociates into its Na+ ion and its negatively charged chain. Since the Na+ ions does'nt take part in the cleaning action of soaps, each sodium stearate molecule has a -ve charge, and hence several of these molecules together ( a micelle) would yield a net -ve charge