The vapor pressure of ethanol (C2H5OH) at 40.85°C is 0.176 atm; at 69.85°C, it is 0.682 atm. (a) Calculate the molar enthalpy of vaporization (AHvap) of ethanol. AHvap = kJ mol-1 (b) Calculate the normal boiling point of ethanol. Normal boiling point = °C

When steam condenses to liquid water, 2.26 kJ of heat is released per gram. The heat from 168 g of steam is used to heat a room containing 6.44 104 g of air (20 ft 12 ft 8 ft). The specific heat of air at normal pressure is 1.015 J/(gC). What is the change in air temperature, assuming the heat from the steam is all absorbed by air?

If 14.5 kJ of heat were added to 485 g of liquid water, how much would its temperature increase?

When 7.11 g NH4NO3 is added to 100 mL water, the temperature of the calorimeter contents decreases from 22.1 C to 17.1 C. Assuming that the mixture has the same specific heat as water and a mass of 107 g, calculate the heat q. Is the dissolution of ammonium nitrate exothermic or endothermic?

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.

Dissolving 6.00 g CaCl2 in 300 mL of water causes the temperature of the solution to increase by 3.43 C. Assume that the specific heat of the solution is 4.18 J/g K and its mass is 306 g. (a) Calculate the enthalpy change when the CaCl2 dissolves. Is the process exothermic or endothermic? (b) Determine H on a molar basis for CaCl2(s)H2OCa2+(aq)+2Cl(aq)

9.46 The heat of fusion of pure silicon is 43.4 kJ/mol. How much energy would be needed to melt a 5.24-g sample of silicon at its melting point of 1693 K?

Which molecule, HF, HCl, HBr, or HI, has the strongest chemical bond?

The heat of neutralization, Hneut, can be defined as the amount of heat released (or absorbed), q, per mole of acid (or base) neutralized. Hneut for nitric acid is -52 kJ/mol HNO3. At 27.3C, 50.00 mL of 0.743M HNO3 is neutralized by 1.00 M Sr(OH)2 in a coffee-cup calorimeter. (a) How many mL of Sr(OH)2 were used in the neutralization? (b) What is the final temperature of the resulting solution? (Use the assumptions in Question 11.)

Which evolves more heat—freezing 100.0 g of benzene or 100.0 g of bromine?