# Need help with A Level Chemistry question please

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#1
A student mixes 100 cm3

of 0.200 mol dm–3 NaCl(aq) with 100 cm3

of

0.200 mol dm–3 Na2CO3(aq).

What is the total concentration of Na+

ions in the mixture formed?

A 0.100 mol dm–3

B 0.200 mol dm–3

C 0.300 mol dm–3

D 0.400 mol dm–3

I read somehwere that you times 0.200 by 0.1 but I dont understand why.

0
3 weeks ago
#2
I found this answered on another thread but I don't know how to link to it. It's called "What is the total concentration of Na+ ions in the mixture formed? CHEMISTRY help".
Hopefully you'll be able to find it from that.
0
3 weeks ago
#3
Work out the number of moles of NaCl and Na2CO3 using the formula mol = conc x vol (in dm3).
The number of mol of Na+ from NaCl is a 1:1 ratio
The number of mol of Na+ from Na2CO3 is 2:1 ratio (each sodium carbonate dissociates to give two Na+ ions).
Now you have the total number of moles of Na+, convert into a concentration by dividing mol by total volume of mixture (in dm3)
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