A pure solid sample of Substance X is put into an evacuated flask. The flask is heated at a steady rate and the temperature recorded as time passes. A graph of the results is shown in the picture. A. Using the graph, what is the melting point of X? B. What phase (physical state) of X would you expect to find in the flask after 9 kJ/mol of heat has been added? Select all that apply: solid, liquid, or gas

How much heat, in joules and in calories, must be added to a 75.0g iron block with a specific heat of 0.449 Jig C to increase its temperature from 25 C to its melting temperature of 1535 C?

A student used a coffee-cup calorimeter to determine the enthalpy of solution for NH4NO3.When NH4NO3 is added to water, there is a decrease in temperature of the solution. Is the solution process exothermic or endothermic? (a) endothermic (b) exothermic

In the 1880s, Frederick Trouton noted that the enthalpy of vaporization of 1 mol pure liquid is approximately 88 times the boiling point, Tb, of the liquid on the Kelvin scale. This relationship is called Troutons rule and is represented by the thermochemical equation liquid gas H = 88 Tb, joules Combined with an empirical formula from chemical analysis, Troutons rule can be used to find the molecular formula of a compound, as illustrated here. A compound that contains only carbon and hydrogen is 85.6% C and 14.4% H. Its enthalpy of vaporization is 389 J/g, and it boils at a temperature of 322 K. (a) What is the empirical formula of this compound? (b) Use Troutons rule to calculate the approximate enthalpy or vaporization or one mole of the compound. Combine the enthalpy of vaporization per mole with that same quantity per gram to obtain an approximate molar mass of the compound. (c) Use the results of parts (a) and (b) to find the molecular formula of this compound. Remember that the molecular mass must be exactly a whole-number multiple of the empirical formula mass, so considerable rounding may be needed.