How many moles of helium are in a balloon filled with 6.02 x 1025 atoms of helium?

As the concentration of hydrogen ions in solution increases, what happens to the pH?

Cities are measurably hotter than the surrounding suburbs

Luminosity is the amount of energy emitted by a star each second. Stars radiate light over a broad range of frequencies in the electromagnetic spectrum, from the low energy radio waves to high energy gamma rays.

Plants are capable of using nitrogen directly from the atmosphere. True false

Which electron shell contains the valence electrons of a radium atom in the ground state? 1. the sixth shell 2. the second shell 3. the seventh shell 4. the eighteenth shell

The properties of elements are arranged by ... A. mass numbers B. atomic masses C. atomic radii D. atomic numbers

When a tire is inflated with air is it a chemical or physical change?

Which isotope is used to date ancient artifacts such as fossils? carbon-12 carbon-14 uranium-238 oxygen-16

If 8.60 grams of methane gas (hint: remember the fuel for the bunsen burner) is in a 2.00 L container at 66oC, what is the pressure in the container?

Insulator in a sentence, with science.