A 0. 025-g sample of a compound composed of boron and hydrogen, with a molecular mass of ~28 amu, burns spontaneously when exposed to air, producing 0. 063 g of b2o3. What are the empirical and molecular formulas of the compound?.

All of the following are examples of service-learning opportunities except: a. donating time to senior citizen war veterans and writing a report about the experience for your u.s. history class. b. getting a part-time job at a habitat restoration center. c. reading to second-grade students as part of your assigned reading time for your english class. d. planting trees in your community and then discussing global warming in your science class.

Arealtor is studying the graph above, which shows the expected value of properties in her area over the next 24 years. if t represents the number of years after 2014, in what year should the increase in property values start to slow down? a. 2008 b. 2018 c. 2022 d. 2030

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.