How many atoms are in 80.45g of magnesium

see below

Explanation:

1. 1 mol Mg = 24.31 g = 6.02 *10^23 atoms

     calculate the number of atomsin 80.45g Mg

         Numberof atoms = 6.02*10^23 Mg atoms / 24.31 g * 80.45 g

                                    = 1.99*10^24 atoms

2.1 mol C-12 = 12.01g = 6.02 * 10^23 atoms

    calculate the mass using

                                       = 12.01 g C / 6.02*10^23 atoms * 100 atoms

                                       = 1.99 * 10^-21 g

the ozone layer acts as a filter for the shorter wavelength and highly hazardous ultraviolet radiation (uvr) from the sun, protecting life on earth from its potentially harmful effects. when the sky is clear, there is an inverse relationship between stratospheric ozone and solar uvr measured at the earth's surface.

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.