Calculate the pH of a buffer consisting of 0.50 M HF and 0.45 M F- (Ka of HF = 6.8 x 10 -4). i) Before addition of NaOH.
ii) After addition of 0.40 g of NaOH to 1.0 L of the buffer.

How many moles of al3+ ions are in 1.25 moles of al2o3

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.

Akno3 solution containing 51 g of kno3 per 100.0 g of water is cooled from 40 ∘c to 0 ∘c. what will happen during cooling?