The heat of fusion of thallium is 21 j/g, and its heat of vaporation is 795j/g. The melting anf boiling points are 304 degress celcius. The specific heat of liquid thallium is 0.13 j/g*c. how much heat is needed to change 243g of solid thallium at 304 degrees celcius to vapopr at 1457 degrees celcius and 1 atm?