the us gained land
They lost all the land west of the Appalachian Mountain to the Louisiana Purchase Territory.
It didn't gain any land. It did lose a lot of land, though.
It depends on the war.
This is a well-known way: (6 steps) lose lone lane land laid lain gain
Missouri was allowed to join the USA as a slave-state. Other territories within the Louisiana Purchase, south of Latitude 36.30, could also join as slave-states.
No, it is more common for them to lose energy.
It is a combination of both. Oceans gain water from water that runs off from land and from precipitation that falls on them. But they also lose water due to evaporation.
As no actual war is specified, the question is unanswerable.
Lots of people die. Land, money, and power are lost if you lose. If you win you can gain land, money, and power but still lose all three.
On politics the Louisiana Purchase had profound effects. The issue of the expansion of slavery became a huge topic, and eventually led to the 36. 30. Economically, it was a bolster, because people had an urge to move West to capitalize on cheap (or free), abundant, fertile land.
Lose
No. Atoms can gain and lose electrons but seldom gain or lose protons.