Apiece of iron can change in different ways. how is iron bending different from iron rusting?

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?

Mercury metal is poured into a graduated cylinder that holds exactly 22.5 ml the mercury used to fill the cylinder mass in 306.0 g from this information calculate the density of mercury

What is the difference between covalent bonds and ionic bonds? covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms. covalent bonds involve the transfer of electrons between charged atoms; ionic bonds involve the sharing of electrons between atoms. covalent bonds involve the sharing of pairs of electrons between atoms; ionic bonds involve the sharing of single electrons between atoms. covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the sharing of protons between charged atoms.