A control variable is one in which . Group of answer choices

there is a change in the independent variable

there are more than 3 dependent variables

no changes take placeusual or common conditions

No changes take place, usual or common conditions.

"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"