In which era did the first fish appear?

a. Carboniferous

b. Paleozoic

C. Mesozoic

d. Permian

How many moles is 1 billion (1 x 10^9) molecules O2

Which is element has atoms with the strongest attraction for electrons in a chemical bond

Kingfishers in new guinea are separated into distinct subspecies. which two subspecies would you expect to be most genetically different from one another?

Which of the following occurs in this system? A. Water does not cross the membrane at all. Water flows equally in both directions. B. There is a net flow of water from the 10% starch solution into the 4% starch solution. C.

Which of the following processes is spontaneous? A). building a house B). launching a satellite into orbit C). drops of dye dispersing in a clear solution D). cleaning your bedroom E). a ball rolling up a hill

What effect can new observations have on a scientific theory

The total number of valence electrons in the phosphate ion is

The reaction below has an equilibrium constant kp=2.2*106 at 298 k. 2cof2 (g) ⇌co2 (g) + cf4 (g) calculate kp for the reaction below. cof2 (g) ⇌12co2 (g) + 12cf4 (g)

The electrical conductivities of the following 0.100 M solutions were measured in an apparatus that contained a light bulb as the indicator of conductivity. Rank the solutions in order of decreasing intensity (brightest to dimmest) of the light bulb.

What is the name of a list of elements arranged according to the ease with which they undergo certain chemical reactions?