A compound is a substance that can be separated into simpler substances only by chemical means.
Answer:

Explanation:
According to the Law of Conservation of Mass, the mass of the products must equal the mass of the reactants.
- mass products = mass reactants
In this problem, the reaction is:

- The reactants are iron and oxygen. We know the mass of the iron sample is 10 grams.
- The product is ferric oxide. The mass of the ferric oxide sample is 18.2 grams.

We want to find how many grams of oxygen reacted. We have to get the oxygen by itself. 10 is being added to oxygen. The inverse of addition is subtraction. Subtract 10 from both sides of the equation.



<u>8.2 grams of oxygen </u>reacted with 10 grams of iron to form 18.2 grams of ferric oxide.
As a solution is contained with 11% by mass of sodium
chloride, this will therefore conclude that the 100g of the solution is
composed of the 11g of the sodium chloride. In which, the correct answer would
be specified as letter c.
A nuclear reaction<span> in which two or more atomic nuclei come very close and then collide at a very high speed and join to form a new type of atomic nucleus.
Hope this helps :)
</span>