The chemical formula of a covalent molecular substance gives the number of atoms per molecule. The formula of a covalent network or ionic compound gives the simplest ratio of atoms/ions in the ...

Chemical reactions make new chemicals. Atoms are rearranged during a chemical reaction, but the number of atoms does not change. Evidence of chemical reactions includes a large temperature change, ...

People have been brewing beer for millennia, and the basic chemistry of fermentation is well understood. But thanks to advanced analytical techniques, scientists continue to learn more about the many ...