A neutral atom of beryllium (Be) has an average mass of 9 amu and 4 electrons. How many neutrons does it have?

When svante arrhenius first proposed his acid-base theory, he was a doctoral candidate. his professors thought his ideas were unfounded. within a decade, the arrhenius theory of acid-base was widely accepted and praised within the scientific world. arrhenius defined acids as compounds having ionizable hydrogen and bases as compounds with ionizable a) barium. b) hydronium. c) hydroxide. d) oxygen.

Two nitro no2 groups are chemically bonded to a patch of surface. they can't move to another location on the surface, but they can rotate (see sketch at right). it turns out that the amount of rotational kinetic energy each no2 group can have is required to be a multiple of ε, where =ε×1.010−24 j. in other words, each no2 group could have ε of rotational kinetic energy, or 2ε, or 3ε, and so forth — but it cannot have just any old amount of rotational kinetic energy. suppose the total rotational kinetic energy in this system is initially known to be 32ε. then, some heat is removed from the system, and the total rotational kinetic energy falls to 18ε. calculate the change in entropy. round your answer to 3 significant digits, and be sure it has the correct unit symbol.

Identify and describe the three ways that mutations affect organisms.