Question

name the term used for 1. solid directly from the gas 2. gas directly formed from the solid

Answer 1

When a solid substance converts directly into gas without going through the liquid phase it is called Sublimation.

On the contrary when gas directly forms into solid omitting the intermediate stage of liquefying it is called deposition or desublimation.

Sublimation is an endothermic process, whereas Desublimation is a thermodynamic process.

Answer 2

1. " Sublimation "

If a solid directly changes its state of solis to gas directly then it do sublimation.

Here in this case it don't chooses through its liquid state.

2. " Desublimation or Sublimation "

If a gas directly forms its solid then it also evolves through sublimation.

Here in this case also liqyid state don't occurs.