Which statement is true?

rocks do not contain any mineral matter.

most rocks are composed of a single mineral.

most rocks are made up of a mixture of minerals.

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

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.