1 Mg (s) + 2 HCl (aq) --> 1 MgCl2 + 1 H2 If 2.50 mol of hydrochloric acid is reacted, how many moles of magnesium chloride is produced?

1.25 moles of magnesium chloride are produced

Explanation:

Based on the reaction:

Mg(s) + 2HCl (aq) → MgCl₂(s) + H₂(g)

1 mole of magnesium, Mg, reacts with 2 moles of hydrochloric acid, HCl, to produce 1 mole of magnesium chloride, MgCl₂ and 1 mole of hydrogen gas.

To solve this question we have to tak, from the chemical equation:

2 mol HCl = 1mol MgCl₂

That means, the moles of MgCl₂ produced from 2.50mol HCl are:

2.50 mol HCl * (1mol MgCl₂ / 2mol HCl) =

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.