Aspirin (acetylsalicylic acid, c9h8o4 ) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolved 2. 00 g of aspirin in 0. 600 l of water and measured the ph. What was the ka value calculated by the student if the ph of the solution was 2. 60?.

In the image, layer a is the topmost layer. layer c contains fossils from the precambrian era. layer b contains dinosaur fossils, and layer a contains fossils of mammals. which two statements are supported by this evidence? 1. mammals lived before the precambrian era. 2. dinosaurs and mammals existed in the precambrian era. 3. dinosaurs evolved after precambrian organisms. 4. precambrian organisms evolved after dinosaurs. 5. precambrian organisms were the first life-forms to become fossilized, according to this sample.