Answer: The energy from sunlight drives the reaction of carbon dioxide and water molecules to produce sugar and oxygen, as seen in the chemical equation for photosynthesis.
Explanation:
A) 10.0g of Iron is

of Iron.
One mole of dihydrogen is required to form one mole of iron, hence you'll need

of dihydrogen.
B) Likewise : 2.50g of Iron is

of Iron, hence we'll need

of Fe2O3.
This is a physical change.