An iron nail rusts when exposed to oxygen. According to the following reaction, how many grams of iron(III) oxide will be formed upon the complete reaction of 31.1 grams of oxygen gas with excess iron?

iron(s) + oxygen(g) → iron(III) oxide(s)

moles iron(III) oxide

100 grams of molten lead (600°c) is used to make musket balls. if the lead shot is allowed to cool to room temperature (21°c), what is the change in entropy (in j/k) of the lead? (for the specific heat of molten and solid lead use 1.29 j/g⋅°c; the latent heat of fusion and the melting point of lead are 2.45 × 104 j/kg and 327°c, respectively.)