If extinction is a normal part of ecosystems, and mass extinctions have happened before, why should humans be concerned about the rising extinction rate? What do current extinctions tell us about our impact on modern environments?

Your roll: experienced electron speech is adressed to: a new "freshman class" of electrons job: write a speech task: you are to pretend that you are giving a speech to a new group of electrons. be sure to mention their placement in an atom, their charge, and their role in chemical bonding (ionic and covalent) be specific!

150.0 grams of asf3 were reacted with 180.0 g of ccl4 to produce ascl3 and ccl2f2. if the actual yield of ccl2f2 was 127 g, what is the percent yield?

What is the vapor pressure of a solution with a benzene to octane?