Is it always possible to identify something as an element compound pure substance or mixture just by looking at it

Blue light waves have more energy than red light waves. Which of these situations most likely produces a photoelectric effect? You may assume that the same metal is used in each situation. Check all that apply.

Explain the difference between rotation and revolution. Then use these terms to explain how Earth, the moon, and the Sun move relative to one anothe

Which element is most likely to be shiny? sulfur (S) boron (B) calcium (Ca) carbon (C) ?

Which of the following experiments follow ethical standards? A.) performing test on animals when the information can be obtained in other ways. B.) experiments done to people who cannot protect themselves. C.

What category of elements does krypton gas belong to? A. metals B. metalloids C. non-metals

Calculate the acid dissociation constant of a weak monoprotic acid if a 0.5M solution of this acid gives a hydrogen-ion concentration of 0.000 1M? Show your work.

Which orbital notation represents a noble gas in the ground state

c. When we heat water up by the Bunsen burner, what temperature is the boiling water? After 10 minutes

Assuming that air contains 78 percent N2, 21 percent O2 and 1 percent Ar, all by volume. How many molecules of each type of gas are present in 1.0 L of air at STP?

Two children are playing tag. Child A who is doing the chasing can run 100m in 24 seconds Child B is running away from child A and can run 64m in 21 seconds.