Question

What statement is an accurate comparison of the properties of compounds and the properties of the elements that the compounds contain?
A.
They are always identical.







B.
They are different.







C.
They are similar.







D.
They represent opposite characteristics.

Answer 1

When elements are combined to form compounds, they undergo chemical change in which the properties of the composing elements are always different from the compounds formed after reaction. The change is not only applicable to the chemical properties of the elements but also the physical states of the substances. Answer then is B.

Answer 2

Answer is: B. They are different.

For examle, balanced chemical reaction of forming water from hydrogen and oxygen:

2H₂ + O₂ → 2H₂O.

During chemical reaction no particles are created or destroyed, the atoms are simply rearranged from the reactants to the products.

Oxygen (element) has boiling point of -183°C and hydrogen has boiling point of -253°C. In this chemical change water (compound) is produced and it has new boiling point, boiling point of water is 100°C.