Calculate the percent composition by mass of iron in Fe(NO3)3

It's 23.14 percent

Explanation:

First, the mass of all the elements are:

N = 14

O = 16

Fe = 56

In this molecule you have 3 atoms of N, and 9 atoms of O, so:

3•14 = 42

16•9 = 144

The whole mass of the molecule is:

56 + 42 + 144 = 242

242/100 = 2.42, so 1% is 2.42

56/2.42 = 23.14%

away from the curb

explanation:

the wheels would then hit the curb if it started to rolling, decreasing the chance of an accident.

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.