We can also use the equation for enthalpy change for physical phase changes. consider the phase change h2o(l) → h2o(g). calculate δhrxn. use δhf values from the table above. δhrxn = -527.6 kj 44.0 kj 527.6 -44.0

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"

thats how its supposed to be

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.