Which element is reduced in this reaction? cr2o72−+3hno2+5h+→2cr3++3no3−+4h2o enter the chemical symbol of the element?

The answer for #3 is c but i don't know why

What type of energy do chemical bonds have? what type of energy is it converted to during chemical reactions? question 15 options: chemical bonds have kinetic energy, which is converted to potential energy during chemical reactions. chemical bonds have electric energy, which is converted to potential energy during chemical reactions. chemical bonds have heat energy, which is converted to kinetic energy during chemical reactions. chemical bonds have potential energy, which is converted to heat energy during chemical reactions.

What is the area in square meters of 448 g ai foil that has a thickness of 23921 nm? the density is 2.70 g/cm