2 Na + Cl2 --> 2 NaCl If 15 mol Na reacts with 15 mol Cl2, what is the theoretical yield of NaCl that could be
formed?

Theoretical yield of NaCl = 877.5 g or 15 moles

Explanation:

Given data:

Number of moles of Na = 15 mol

Number of moles of Cl₂ = 15 mol

Theoretical yield of NaCl = ?

Solution:

Chemical equation:

2Na + Cl₂      →     2NaCl

Now we will compare the moles of Na and Cl₂ with NaCl.

                Cl₂       :        NaCl

                 1          :          2

               15          :         2/1×15 = 30 mol

                Na       :        NaCl

                 2          :          2

               15          :          15

Less number of NaCl are produced by Na it will act as limiting reactant.

Theoretical yield:

Mass = number of moles × molar mass

Mass = 15 mol × 58.5 g/mol

Mass = 877.5 g

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.