Describe the limitations of using models to represent atoms

One of the reactions in a blast furnace used to reduce iron is shown above. how many grams of fe2o3 are required to produce 15.5 g of fe if the reaction occurs in the presence of excess co? a.11.1 g b.22.1 g c.30.0 g d.44.2 g

When the volume and number of particles of a gas are constant which of the following is also constant

Find the mass in grams of 1.37x1020 particles of h3po4