Manipulation of Enthalpies vs. K values

[Vishwa Diwan 1D]

If I recall correclty, when using Hess's law to manipulate K values, why was it that we would take the inverse of the K for reverse reactions and then if multiplied/divided a reaction, then the K value would be raised to that factor number, but when we manipulate enthalpies and change of H for chemical equations, it is simply the sum or subtraction or multiplication of these numbers?

[Nils Newman 1F]

I think this is because enthalpy is a state value. For example, if we mixed two solutions together, the total enthalpy would just be the sum of the enthalpies of the two solutions plus or minus any enthalpy that was lost or gained due to the reaction.
But for K, if you where to say mix a solution where K = 1 and a solution where K = 3, you would not get K = 4.

[Justin Selby 2G]

To add on, the same principle of manipulating the K value is true for the delta H, only with different rules. Enthalpy is much easier because all you have to do is multiply the number of delta H by whatever you're multiplying the equation by, and reverse the sign if you reverse the direction of the equation in your calculations.

[Anjali Mathew 3D]

Yep, for modifying enthalpies, you just multiply when you increase the number of moles by a certain value in a reaction (2 times deltaH), and divide when you have a reaction enthalpy that gives you double the moles that you want. Therefore, this value doesn't have to be squared, or taken the inverse of. This difference is because enthalpy is dependent on its current state, not how exactly it got there - therefore, its values will be the same even with this kind of manipulation. You can also add, subtract enthalpies because of this.