Every kind of element is made up of its own kind of?

Correct relationship between molecular formula and empirical formula

At stp, which substance is the best conductor of electricity? a. nitrogen b. neon c. sulfur d. silver

4.25g sample of solid ammonium nitrate dissolves in 60.0g of water in a coffee-cup calorimeter, the temperature drops from 22.0 c to 16.9 c. assume that the specific heat of the solution is the same as that of pure water. calculate delta(h) (in kj/mol nh4no3) for the solution proces.