YOU DO: 1) What volume of 0.25M lithium fluoride solution can be made by dissolving 5.0 g lithium fluoride, LiF?

0.7712 L

Explanation:

Molarity = 0.25M

Volume = ?

Mass = 5.0 g

The relationship between these quantities is given as;

Molarity = Number of moles / Volume

Volume = Number of moles / Molarity

Number of moles = Mass / Molar mass

Molar mass of LiF = 25.939 g/mol

Number of moles  = 5 / 25.939 = 0.1928 mol

Volume = 0.1928 / 0.25 = 0.7712 L

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.