HELP ASAP FIRST PERSON WITH CORRECT ANSWER WILL RECEIVE BRAINLIEST In a chemical reaction, atoms are rearranged to form new substances. This happens
predictably. The same reactants will form the same products no matter when or where the reaction takes place. For example, in a lab, you could combine iron and oxygen. The product will be the same iron oxide that forms on a rusty iron nail. Those are the same reactions. Similarly, if you've studied acids and bases, you probably know the products of a neutralization reaction. Acids and bases will combine in a chemical reaction to produce a
salt and water. Based on the passage, rust will form on an iron nail when what has occurred?
A
a neutralization
B
an acid has combined with a base
С
salt has reacted with water
D
iron has reacted with oxygen

the answer is the

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

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year