A contact force is a force in which and object comes in contact with a another object. A non-contact force, is a force is an object applied by another body. (A good example of a non-contact force is gravity)
Answer:
2Fe(s) + 3O2(g) --------> 2FeO3(s)
Explanation:
According to the question, a battery was used to light the steel wool by bringing the terminals very close together. When the battery came into contact with the steel wool, current was sent out through the thin wire. This caused the iron to heat up quite well.
Iron reacts with oxygen under these conditions as follows;
2Fe(s) + 3O2(g) --------> 2FeO3(s)
This is the chemical reaction that occurs when the steel wool is set on fire.
Atomic mass (K)= 39.1 amu
therefore:
1 mol (k)---------------------39.1 g
x------------------------------- 2.25 g
x=(1 mol * 2.25 g) / 39.1 g=0.05754....≈0.06 moles
Answer: 0.06 moles.