Given a 0.5 M stock solution of aqueous NaCl, how much of the stock solution would you need to make a 50 mL sample of 0.25 M aqueous NaCl solution? How much water would you need to add to the NaCl solution?

Darla claims that the first periodic table developed by mendeleev was not completely accurate, so it is not useful at all. harmony argues that it establish the periodic table we use today, making it more credible. who is correct and why? darla is correct, because a model that has any mistakes should be thrown out. darla is correct, because a good model would not need to change. harmony is correct, because mendeleev’s model had all of the information correct in the first version. harmony is correct, because mendeleev’s model made predictions that came true.

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

How many mmols of tris-hcl are there in 100 ml of a 100 mm tris-hcl buffer solution at ph 8.1? note that the 100 mm refers to the sum of tris and tris-hcl concentrations?