[3 Fe + 2 O2 → Fe3O4], How many moles of Fe3O4 will be produced from 2.8 mol Fe with an excess of Oxygen gas?

Asample of aluminum foil contains 8.60 × 1023 atoms. what is the mass of the foil?

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.

The three types is stress that act on earths rocks are compression, tension, and