x Turn on thread page Beta
 You are Here: Home

# chemistry help watch

1. what volume of 0.05mol dm-3 KOH is required to exactly neutralise 24.0 cm3 of 0.11 mol dm-3 H2SO4 according to the equation 2KOH +H2SO4= K2SO4+2H2O??
2. First work out the number of moles of H2SO4 that you have.

0.11 moldm-3 * 24.0 * 10^-3 dm3 = 2.64*10^-3 moles of H2SO4.

Each mole of H2SO4 reacts with two moles of KOH (just look at the equation)

Therefore 5.28*10^-3 moles will react.

5.28*10^-3 moles / 0.05 moles dm-3 = 105.6 * 10^-3 dm3

This is 105.6 cm3.

The key to a lot of these questions is just to use standard form of some description. I use engineering notation which involves powers of three only, as this makes unit conversions straightforward. Just remember to always replace dm3 with * 10^-3 cm3 and you'll be fine.
3. I just attempted this question and got an answer a bit different. i worked out the number of moles of h2so4 and converted this answer to dm3 by dividing this by the concentration(since volume=moles/concentration). since this volume is only for one mole of h2so4 I multiplied this by 2(to get 2 moles of koh).

my answer was 0.1078 dm3, is this right?

Posted from TSR Mobile
4. (Original post by zaaraxo)
I just attempted this question and got an answer a bit different. i worked out the number of moles of h2so4 and converted this answer to dm3 by dividing this by the concentration(since volume=moles/concentration). since this volume is only for one mole of h2so4 I multiplied this by 2(to get 2 moles of koh).

my answer was 0.1078 dm3, is this right?

Posted from TSR Mobile
We are within 2% so the difference will just be down to rounding. That's a new method I had never thought of, will have to try it.

Posted from TSR Mobile

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: October 28, 2015
Today on TSR

### How much will your degree earn you?

Find out where yours ranks...

### I do my boyfriend's uni assignments

Poll
Useful resources

Can you help? Study Help unanswered threadsStudy help rules and posting guidelines

## Groups associated with this forum:

View associated groups

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