"the discovery of the atom"

the atomic theory began as an ancient philosophy dating back to at least the fifth and sixth centuries bce in both greece and india. in fact, the word atom is taken from the greek word “atomos,” meaning indivisible. the term atom was used to define the basic particle that made up a chemical element. chemists during the time of the ancient greeks believed that atoms were the fundamental particles of matter. in other words, the atom was thought to be the smallest possible unit that matters could be broken down into. this basic philosophy proposed that a solid object could potentially be divided again and again until it eventually reached the smallest indivisible unit—an atom. followers of this ideology were called atomists. in the fifth century, a greek philosopher named leucippus and his pupil democritus proposed that all matter was made up of atoms.
what is paragraph 2 most likely about?
a) the properties of an atom
b) the beginning of atomic research
c) the creation of religious philosophy
d) the connection between atoms and religion

answer:

atoms

explanation:

one state would change   like louisiana to texas. thats a change

explanation:

part 1: the half-life of the element is 22 years.

part 2: it will take 132.02 year for the sample to decay from 308.0 g to 4.8125 g.

explanation:

part 1: there are two ways to determine the half life time.

first way: the half life time can be determined directly from its definition as it is the time required for the sample to decay to its half concentration.

from the data the initial concentration was 45.0 g and decayed to its half value (22.5 g) in 22.0 years.

second way: the radio active decay is considered first order reaction so we can use the laws of first order reactions.

k = (1/t) ln (a/a-x), where k is the rate constant of the reaction,

t is the time of the reaction

a is the initial concentration of the reactant

a-x is the remaining concentration at time (t)

a = 45.0 g the initial concentration at t = 0 year.

at t = 22 year, a-x = 22.5 g

then k = (1/22 year) ln (45.0 g/ 22.5 g) = 0.0315 year-1.

the half-life time (t1/2) = ln 2/ k = 0.693/ k =0.693/ 0.0315 = 22 years.

part 2:

using the same law k = (1/t) ln (a/a-x),

using the given data; a = 308.0 g and a-x = 4.8125 g and the calculated k from the part 1 (k = 0.0315 year-1)

t = (1/k) ln (a/a-x) = (1/0.0315) ln (308.0/ 4.8125) = 132.02 years