What does it mean to state that two stars are 100 light-years apart?

What will most likely happen when two bromine atoms bond together?

What is the atomic mass of an atom that has 6 protons, 6 neutrons, and 6 electrons? a) 6 b) 8 c) + 1 d) 12 e) 18

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.