Determine the boiling point in Ce

The cooling effect of alcohol on the skin is due to its evaporation. Calculate the heat of vaporization of ethanol (ethyl alcohol), C2H5OH. C2H5OH(l)C2H5OH(g);H=? The standard enthalpy of formation of C2H5OH(l) is 277.7 kJ/mol and that of C2H5OH(g) is 235.1 kJ/mol.

The enthalpy change when 1 mol methane (CH4) is burned is 890 kJ. It takes 44.0 kJ to vaporize 1 mol water. What mass of methane must be burned to provide the heat needed to vaporize 1.00 g water?

If you want to convert 56.0 g ice (at 0 °C) to water at 75.0 °C, calculate how many grams of propane, C3H8, you would have to bum to supply the energy to melt the ice and then warm it to the final temperature (at 1 bar).

Define the joule in terms of SI base units.

A student is asked to calculate the amount of heat involved in changing 10.0 g of liquid bromine at room temperature (22.5C) to vapor at 59.0C.To do this, one must use Tables 8.1 and 8.2 for information on the specific heat, boiling point, and heat of vaporization of bromine. In addition, the following step-wise process must be followed. (a) Calculate H for: Br2(l,22.5C)Br2(l,59.0C) (b) Calculate H for: Br2(l,59.0C)Br2(g,59.0C) (c) Using Hess's law, calculate H for: Br2(l,22.5C)Br2(g,59.0C)

9.47 If 14.8 kJ of heat is given off when 1.6 g of HCl condenses from vapor to liquid, what is Hcond for this substance?

Phosphorus exists in multiple solid phases, including two known as red phosphorus and white phosphorus. (a) Based on their respective heats of formation, which form of phosphorus is defined as the standard state? (b) Now consider the phase transition between white and red phosphorous: P4(s, white4 P(s, red). Use data from Appendix E to determine which form of phosphorous is actually more stable at 25C. (Your result should reveal that phosphorus is an exception to the usual convention for defining the standard state.) (c) Is the same form of the solid more stable at all temperatures? If not, what temperatures are needed to make the other form more stable?

The enthalpy of combustion of liquid n-hexane, C6H14, is 4159.5 kJ/mol, and that of gaseous n-hexane is 4191.1 kJ/mol. Use Hesss law to determine H for the vaporization of 1 mol of n-hexane: C6H14() C6H14(g)

Hesss law is really just another statement of the first law of thermodynamics. Explain.