A. They are a mixture of an element and compounds.                                                                   

B. They are a mixture of elements.

C. They are a mixture of compounds

D. They produce a new compound.

E. These are all pure substances, and therefore they do not mix.

A. The chemical formula for a compound contains two or more different elements while the chemical

formula for an element only shows one type of atom.                                                                   

B. The chemical formula for a compound always contains two elements while the chemical formula for an

element is shorter.

C. The chemical formula for a compound is simpler than the chemical formula for an element.

D. The chemical formula for an element is made up of only one atom while the chemical formula

for a compound will always have more than one atom.

E. The chemical formula for a compound contains two or more different types of atoms, indicating that it is a mixture of elements.

A. 2, 3, and 5                                                                                                                                  

B. 1, 2, and 3

C. 2, 3, and 4

D. 3, 4, and 5

E. 1, 2, and 5

A. 14.7 grams SO₂                                                                                                                          

B. 4.37 grams SO₂

C. 280 grams SO₂

D. 54.6 grams SO₂

E. 0.85 grams SO₂

5.  For many years alchemists tried to convert lead to gold. All of the following reasons for their failure are true EXCEPT

A. To change lead into gold, alchemists needed to remove three protons from the nucleus of lead.

B. Alchemists were not able to "cook" the reaction hot enough to provide the energy required to remove protons

from the lead nucleus. The energy required to overcome the lead atom's binding energy is enormous compared to the amount supplied by alchemist's "cooking".

 C. Alchemists did not know then that it is impossible to add or remove particles from the nucleus of an atom.

D. Alchemists were conducting ordinary chemical reactions, which only involve valence electrons and

not the nucleus. In chemical reactions atoms can change partners but not change their elemental identity

E. Reacting lead carbonate with acid, alchemists only broke old bonds and formed new ones.

Breaking bonds requires only a fraction of the energy required to overcome the binding energy in the nucleus.