Which of the following is the best description of a chemical reaction? a. when molecules of a substance move slowly enough, they link together to form a crystalline structure. b. when two molecules collide with enough force, old chemical bonds are broken and new bonds form, resulting in one or more new substances. c. when two molecules collide with enough force, they shatter into individual atoms. later, these atoms join up in new combinations to form new substances. d. when two atoms collide with enough force, their nuclei fuse together, forming new substances and releasing tremendous amounts of energy.

Lab reagent, hypothesis test.a reference solution used as a lab reagent is purported to have a concentration of 5 mg/dl. six samples are taken from this solution and the following concentrations are recorded: (5.32, 4.88, 5.10, 4.73, 5.15, 4.75) mg/dl.these six measurements are assumed to be an srs of all possible measurements from solution.they are also assumed to have a standard deviation of 0.2, a normal distributin, and a mean concentration equal to the true concentration of the solution.carry out a significance test to determine whether these six measurements provide reliable evidence that the true concentration of the solution is actually not 5 mg/dl.