You are Here: Home

# limiting reagant Watch

1. Hi I was wondering if anyone could help me out with this question, it keeps going over my head.

Q) 20cm^3 of 0.2 mol l^-1 sulphuric acid is added to 50cm^3 of 0.1 mol l^-1 barium chloride solution.
a- calculate which reactant is in excess
b- what mass of barium sulphate would be precipitated?

I keep on getting the sulphuric acid as the excess and 1.167 g of product. the answer at the back says barium chloride is in excess and 0.934 g is produced. can someone please help me out?
any answers would be greatly appreciated and also how much studying have yous been doing for your highers?
Thanks.
2. I always start by writing out the chemical equation: H2SO4 + BaCl2 ---> BaSO4 + 2HCl

You need to work out the amounts in moles. From the equation above we can see that one mole of sulfuric acid reacts with one mole of barium chloride - easy peasy.

moles (mol) = volume (dm3) x concentration (mol dm-3)

H2SO4 = 0.020 x 0.2 = 0.004 mol
BaCl2 = 0.050 x 0.1 = 0.005 mol

There is more barium chloride than sulfuric acid, so it is in excess. Make sense?

We then use the limiting reagent (the one not in excess) to calculate the mass of the barium sulfate. Does that help?

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: April 17, 2014
Today on TSR

### Living with thieves

My housemates are stealing my food

### Should I WhatsApp him?

Poll

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.