How do you use a model to describe how the total number of atoms does not change in a chemical reaction and thus mass is conserved.

Bohr's model could only explain the spectra of which type of atoms? single atoms with one electron single atoms with more than one electron bonded atoms with one electron bonded atoms with more than one electron

The pressure inside a hydrogen-filled container was 2.10 atm at 21 ? c. what would the pressure be if the container was heated to 92 ? c ?

Use examples from the article to explain one positive and one negative effect that chemistry has had on society.