The Law of Conservation of Mass<span> states that </span>matter <span>can neither be created nor destroyed in a chemical reaction.</span>
The correct answer is option 3. The IUPAC name is Iron(II) sulfide. It is the less stable amorphous form. When this is powdered, it is pyrophoric or it ignites spontaneously in air. It readily reacts with hydrochloric acid producing hydrogen sulfide.
The momentum of the body is 12 m/s.
<h3>What is momentum?</h3>
Momentum is the product of the mass of a body and velocity. According to Newton's second law, the rate of change of momentum is equal to the impressed force.
The details required to answer the first two questions are missing hence we can't answer those questions. For the last question;
p = mv
m = mass
v = velocity
p = momentum
v = p/m
v = 72,000 kgm/s/6,000 kg
v = 12 m/s
Learn more about momentum: brainly.com/question/904448
A is correct hope this helps