What form of matter is vapor?
a solid made of a substance that is usually liquid
a liquid made of a substance that is usually gas
a gas made of a substance that is usually solid
a gas made of a substance that is usually liquid

The form of matter that is vapor is a gas made of a substance that is usually liquid. 
Vapor is created when water, or some other liquid evaporates - meaning that it becomes so hot in a room, or wherever, that the liquid starts becoming gas. 

Answerthe energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.explanationwe define electric potential as the ratio electric potential energy to the charge,    then the following gives us the potential difference,      the formula  may be on your formula sheet.the change in electric potential energy would be the energy that would needed to move it from point a to point b. solving for that, we get    using q = 8.00  × 10⁻¹⁹ c and  δv = 2.00 v, we get    the energy required is 1.60 × 10⁻¹⁸ j, to three significant figures.