Effect of Solvent: Record the results.
H2O =
alcohol =
glycerin =
In which liquid is the salt most soluble?
Using the concept of `'Like dissolves like," explain why you got the results you did.
Explain how the choice of solvent affects the dissolving process.
Effect of Pulverizing:
Record of dissolving times.
crystal =
pulverized =
Why are the dissolving rates different?
Effect of Temperature:
Record of dissolving times.
cold =
hot
Using the concepts of kinetic energy, describe why you found the results you did.
Effect of Stirring:
Record the times necessary to dissolve each sample.
Record of dissolving time.
stirred =
unstirred =
Perform the experiment again using hot tap water this time. Are there any differences in the results between the cold water experiment and the hot water experiment? Explain.
Conclusions:

Review the four factors of dissolving you have just investigated. Given the correct solvent for a solute, what could you do to hasten the solution process?

1.

2.

3.

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

the dependant variable is spilled water

the independent is the heat