An air-water vapour mixture has a dry-bulb temperature of 333 k and a dew-point temperature of 313 k. the total pressure is 101.3 kpa and the vapour pressure of water at 313 k is 7.3 kpa and that at 333 k is 19.91 kpa. the humidity of air expressed as kg of water vapour per kg of dry air is (a) 0.048 (b) 0.079 (c) 0.122 (d) 0.152

po-215 i got it right on the quiz

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.

they are all solids.