Achemist prepares a solution of nickel(ii) chloride nicl2 by measuring out 21.μmol of nickel(ii) chloride into a 200.ml volumetric flask and filling the flask to the mark with water. calculate the concentration in /mmoll of the chemist's nickel(ii) chloride solution. round your answer to 2 significant digits.

Write the chemical symbols for three different atoms or atomic cations with 27 electrons. asap!

If you add 5.00 ml of 0.100 m sodium hydroxide to 50.0 ml of acetate buffer that is 0.100 m in both acetic acid and sodium acetate, what is the ph of the resulting solution? acetic acid: ka = 1.8. x 10-5

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.