Posted by Lily on Saturday, June 28, 2014 at 7:27pm.
A solution of X2CO3 has a concentration of 15.2 g/dm^3. 25 cm^3 of this solution require 27.5 cm^3 of 0.2 M HCl for complete reaction. Calculate the ralative atomic mass of X

Chemistry  Damon, Saturday, June 28, 2014 at 7:54pm
1 dm^3 = 1000 cm^3 = 1 liter
so
X2CO3 is 15.2 g/liter
a liter of this requires 27.5/25 or 1.1 liters of .2 M HCl
1.1 * .2 = .22 mols of HCL
X2CO3 + 2 HCl > 2 XCl + H2CO3 maybe?
so we only need .11 mols of X2CO3
.11 mols of X2CO3 weigh 15.2 grams
1 mol X2CO3 weighs 138 grams
C is 12
O3 is 48
138  12  48 = 78
so X2 is 78 so x is 39
(Potassium? K2CO3 )