When a chemical reaction is at equilibrium, which of the following statements is always true?
a. the equilibrium constant keq= 1.
b. the ratio of the concentrations of reactants and products equals 1.
c. the rate of the forward reaction is equal to the rate of the backward reaction.
d. all of the choices are correct.

George is a dalmatian puppy. describe what happens to light that allows you to see george’s black and white coat.

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.

About 3% of the water on earth is freshest. only about 40% of that freshwater is available for human use. why is so much freshwater unavailable for human use?