Help asap What are elements in the tall columns of the periodic table called?
A. Representative elements
B. Valence elements
C. Atomic elements
D. Period elements

How can carbon move from "land" to bodies of water? describe the way human impact has lead to increased levels of co2 in the atmosphere.

)benzene and toluene form nearly ideal solutions. consider an equimolar solution of benzene and toluene. at 20 °c the vapour pressures of pure benzene and toluene are 9.9 kpa and 2.9 kpa, respectively. the solution is boiled by reducing the external pressure below the vapour pressure. calculate (i) the pressure when boiling begins, (ii) the composition of each component in the vapour, and (iii) the vapour pressure when only a few drops of liquid remain. assume that the rate of vaporization is low enough for the temperature to remain constant at 20 °c.

If one fission reaction of a uranium-235 atom produced two neutrons, how many neutrons would be released if the chain reaction occurred three more times?