A student wants to prepare 400 mL of buffer with a pH of 4.90 using acetic acid and sodium acetate. a) What should be the acid-salt molar ratio for the buffer? b) If he prepares the solution at a HOAc concentration of 0.12M, how many grams of NaOAc must he add to obtain the desired pH?

the answer is b because, investigating whether another species of moth also drinks tears might be interesting, but it would not directly explain why this species of moth does.

to explain why this species of moth drinks tears, the scientist could ask: "what nutrients that moths need are in elephant tears? "

the scientist could experiment with moth repellent or oter ways to keep the moths away, but that would not answer his original question.