Density can be defined as the mass of a sample present per unit volume.
Given the volume of air = 125 mL
Converting air from mL to L,
Density of air = 1.197 g/L
Calculating the mass of air from density and volume:
Mass of air =
Therefore, the mass of 125 mL of air with a density of 1.197 g/L is <u>0.150 g</u>
B I think but not 100% sure
Iron (II) oxide is composed of iron with an oxidation number of +2 (shown by the II after iron) and an oxygen that has an oxidation number of -2 (oxygen almost always has an oxidation state of -2). Since the anion and cation both have a charge of +or- 2, they bond with each other with a 1 to 1 ratio and the formula should be FeO
I hope this helps. Let me know if anything is unclear.