The three isomers of pentane have different
(1) formula masses
(2) molecular formulas
(3) empirical formulas
(4) structural formulas

Modern weaponry has increased the number of deaths in wars and violent conflicts.

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?