A g A mixture of Fe, FeO and Fe2O3 is dissolved in exactly 240mL 1mol L of dilute nitric acid to form Fe (NO3)2, H2O and 0.03molNO, The following is the correct judgment for the ag mixture A. The mass of the iron element was 2.52 g B.Fe2O3, and the mass was 8.40 g C. The amount of iron is 0.105mol D. the ratio of iron to oxygen is 7:4 I figured it out Fe0.045mol FeO0.06mol Fe2O3 0 Mol I chose ACD. But why is CD the only answer?

A g A mixture of Fe, FeO and Fe2O3 is dissolved in exactly 240mL 1mol L of dilute nitric acid to form Fe (NO3)2, H2O and 0.03molNO, The following is the correct judgment for the ag mixture A. The mass of the iron element was 2.52 g B.Fe2O3, and the mass was 8.40 g C. The amount of iron is 0.105mol D. the ratio of iron to oxygen is 7:4 I figured it out Fe0.045mol FeO0.06mol Fe2O3 0 Mol I chose ACD. But why is CD the only answer?

FeO+2HNO3-> Fe (NO3)2+2H2O
0.06 0.12
3Fe+8HNO3->3Fe (NO3)2+2NO+4H2O
0.045 0.12 0.03
My result is also ACD, is there a problem with the answer?

The concentrated sulfuric acid with a dilution mass fraction of 98%(density of 1.84 g/mL) is prepared into 500 mL of dilute sulfuric acid with a mass fraction of 20%(density of 1.14 g/mL), and the volume of water required for dilution is about () A. 436.8mL B. 453.7mL C. 456.0mL D. 458.3mL

Set the mass of concentrated sulfuric acid required for dilution as x
500ML×1.14g/mL×20%=x×98%
X ≈116.3 g
Mass of water added =500 mL ×1.14 g/mL-116.3 g =453.7 g
Since the density of water is 1 g/mL, its volume is 453.7 mL.
Therefore, B.