In an open system the vapor pressure is equal to the

In an open system the vapor pressure is equal to the outside air pressure.

Explanation:

An open system is a system that is capable of exchanging both matter and energy with its surroundings.

For example, a hot cup of coffee is an open system as the cup is not covered with a lid. Therefore, heat energy from the coffee goes into the surroundings.

Vapor pressure is defined as the ability of a substance to change into vapor state. pressure

Therefore, we can conclude that in an open system the vapor pressure is equal to the outside air pressure.

it can be observed without changing the identity of the object.

it depends on what substance you're talking about as well as many other factors. in quantum mechanics, the observation of particles affects the observers ability to measure certain properties. for example: you can know the velocity of a particle, but you can't know it's position; or you can know it's position, but not it's velocity. it's like trying to find out where a grain of sand is by throwing other grains of sand at it. once you find out where it is, it's been moved. it's also like trying to find an answer to the question of whether or not a tree falling in a forest makes a sound if nobody is there to hear it. paradoxically, the only way to find out is to be there and hear it.

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.