A student adds iron filings to a copper(II) chloride solution at room temperature. A balanced equation
for the reaction that occurs is shown below.
Fe(s) + CuCl2(aq) - FeCl2(aq) + Cu(s)
Which of the following changes would most likely
increase the reaction rate?
A. using larger pieces of iron
B. performing the reaction in an ice bath
C. decreasing the volume of the CuCl2 solution
D. increasing the concentration of the CuCl2
solution

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.