Which is an example of a solution?
a. flour and water
b. sand and water
c. salt and water
d. oil and water
e. ice and water

salt and water

Explanation:

Mixture:

A mixture is made from two or more type of matter in any proportion. Mixture are generally two types:

1.Homogeneous mixture

This is also known as solution, in which the composition of the substances is uniform.

Lemon-flavored water is an example of homogeneous mixture because in this the composition of the substances is uniform.

2.Heterogeneous mixture

In this form of mixture the composition of substance are not uniform and the component of mixture also visible.

Stuffed mushrooms is an example of Heterogeneous mixture because in this form of mixture the composition of substance are not uniform and the component of mixture also visible.

a.flour and water : Heterogeneous mixture

b.sand and water Heterogeneous mixture

c.salt and water Homogeneous mixture Or solution because in which the composition of the substances is uniform.

d.oil and wate Heterogeneous mixture

e.ice and water Heterogeneous mixture

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