You are Here: Home

# Acid-base titration calculations

Announcements Posted on
Why bother with a post grad course - waste of time? 17-10-2016

1. Any help with question 2 would be hugely appreciated! Thank you.
2. (Original post by jamiescriven)

Any help with question 2 would be hugely appreciated! Thank you.
So your two reactants are HCl and NaHCO3.

(33.2X0.1)/1000= 3.32x10-3 mols of HCl.
The molar ratio is 1:1 so there are also 3.32x10-3 mols of NaHCO3
This is for 25cm3 however so multiply by 10 which gives 0.332 mols of NaHCO3 in 250cm3.
This needs to be converted into grams:
The Mr for NaHCO3 is 84.
84X0.332= 2.7888g of NaHCO3 in the tablet.
(2.7888/mass of tablet in total)X100= 58.6% which is the % by mass of NaHCO3 in the tablet.
3. (Original post by JimJam456)
So your two reactants are HCl and NaHCO3.

(33.2X0.1)/1000= 3.32x10-3 mols of HCl.
The molar ratio is 1:1 so there are also 3.32x10-3 mols of NaHCO3
This is for 25cm3 however so multiply by 10 which gives 0.332 mols of NaHCO3 in 250cm3.
This needs to be converted into grams:
The Mr for NaHCO3 is 84.
84X0.332= 2.7888g of NaHCO3 in the tablet.
(2.7888/mass of tablet in total)X100= 58.6% which is the % by mass of NaHCO3 in the tablet.
NaHCO3 is sodium bicarbonate right? But in the question it says the second reactant is hydrated sodium carbonate, so wouldn't that be NaCO3.xH2O?
4. (Original post by jamiescriven)
NaHCO3 is sodium bicarbonate right? But in the question it says the second reactant is hydrated sodium carbonate, so wouldn't that be NaCO3.xH2O?
Sodium Hydrogen Carbonate. Considering the information available that's the only thing I thought it could be.
5. (Original post by jamiescriven)
NaHCO3 is sodium bicarbonate right? But in the question it says the second reactant is hydrated sodium carbonate, so wouldn't that be NaCO3.xH2O?
It would but you're only interested in finding the mass of NaHCO3 and then comparing it to the actual mass of the tablet, so the actual structure of the hydrated bicarbonate is irrelevant.

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: March 30, 2016
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:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

### Nintendo NX big reveal!

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.