You are Here: Home

# Calculating total moles when ions dissolve in water? watch

1. So I need to calculate the total moles of ions released when each of the following dissolves in water.

a)0.61 mol Rb2SO4
b) 3.85x10^-3g CaCl2
c)0.2 mol sucrose
d)3.7x10^25 molecular units of ammonium bichromate

I just need clarification on c)

Since sucrose is C12H22O11, would the ions released be C12, H22 and O11?
2. sucrose has 8 OH groups which I suppose dissociate in water to form H+ ions.
3. (Original post by tremen222)
sucrose has 8 OH groups which I suppose dissociate in water to form H+ ions.
No, hydroxyl groups do not dissociate in water.
4. (Original post by charco)
No, hydroxyl groups do not dissociate in water.
I was thinking that, although it does depend on whether the pKa of sucrose is >14.
Does the question mean then that the sucrose hydrolyses into glucose and fructose?
Alternatively it could be that the answer is just 0 moles as sucrose does not ionise at all in water.
5. (Original post by tremen222)
I was thinking that, although it does depend on whether the pKa of sucrose is >14.
Does the question mean then that the sucrose hydrolyses into glucose and fructose?
Alternatively it could be that the answer is just 0 moles as sucrose does not ionise at all in water.
You are overthinking the question.

Sucrose is simple covalent and does not produce ions when dissolved.

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: February 15, 2018
The home of Results and Clearing

### 2,541

people online now

### 1,567,000

students helped last year
Today on TSR

### University open days

1. Keele University
Sun, 19 Aug '18
2. University of Melbourne
Sun, 19 Aug '18
3. Sheffield Hallam University