Calculate the mass in grams of 1.2044 x 10^24 atoms of lead (Pb).

A.) 207.2 g
B.) 2.0 g
C.) 0.50 g
D.) 414.4 g

414.14g

Explanation:

From Avogadro's hypothesis, we understand that 1mole of a substance contains 6.02x10^23 atoms.

From the above, it is evident that 1mole of Pb will also contain 6.02x10^23 atoms.

1mole of Pb = 207g/mol

207g of Pb contains 6.02x10^23 atoms.

Therefore, Xg of Pb will contain 1.2044 x 10^24 atoms i.e

Xg of Pb = (207x1.2044x10^24)/6.02x10^23 = 414.14g

it is to be noted that an alpha particle is an helium nucleus. so it contains 2 protons 2 neutrons and has a mass number of 4. when alpha decay particles are ejected from the nucleus it gets transformed into an atom which has atomic number less than 2 and a mass number less than 4.

an equation that could represent alpha decay is radium 226 decay of alpha particle forms radon 222.

→

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.