7.15g of Na2Co3.xH2O is dissolved in 250cm^3 of distilled water to form 0.10mol/dm^3.The entire solution was reacted with HCL to produce NaCl, H2O and 8960cm^3 of CO2 gas at stp in a beaker. Calculate 1.the contentration of Na2CO3.xH2O in g/dm^3
2.the molar mass of Na2CO3.xH2O

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"

i would say b

explanation:

but i think i would need more information than that

if you're asking what comes out, it's steam.

the answers would be

the first one and the second one