How to figure out how much a mole would weigh?

Which is the layer underground where all empty spaces are filled with a combination of air and water ?

What type of electromagnetic radiation has a shorter wavelength than blue light

Write the formula for the following chemicals. 7. e. trinitrogen tetraoxide a calcium phosphate f. magnesium acetate b. potassium sulfide g nickel(iii) cyanide c carbon dioxide h. silver sulfate d. cobalt(ii) chloride