Please help me! i really need the answer i’m crying lol

What is the ph of a solution that has a hydrogen ion concentration of 1.0 * 10 -9 m?

Ajet plane is speeding down the runway during takeoff. air resistance is not negligible. identify the forces on the jet.

For a research project, a student decided to test the effect of the lead(ii) ion (pb2+) on the ability of salmon eggs to hatch. this ion was obtainable from the water‐soluble salt, lead(ii) nitrate, which the student decided to make by the following reaction. pbo(s) + 2 hno3(aq) → pb(no3)2(aq) + h2o losses of product for various reasons were expected, and a yield of 86.0% was expected. in order to have 5.00 g of product at this yield, how many grams of pbo should be reacted? (assume that sufficient nitric acid, hno3, would be used.)