Substance A has a normal melting point of - 25.0 degrees * C , an enthalpy of fusion of 1200 J g-1; specific heats for the solid and the liquid are 3.00 and 6.20 Jg-1 °C -1, respectively. To change 150 grams of A from a solid at - 40.0 degrees * C to a liquid at + 70.0 degrees * C

Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ