2. If a compound contains \( 40 \% \) sulfur and \( 60 \% \) oxygen by mass, what is the empirical formula of the compound? (Atomic masses: \( \mathrm{S}=32 \mathrm{~g} / \mathrm{mol}, 0 \) \( =16 \mathrm{~g} / \mathrm{mol} \) )

SECTION 3: Balance the following chemical reactions. a. \( \frac{\mathrm{Zn}}{\mathrm{Zinc}+\underset{\text { Hydrochloric Acid }}{\mathrm{HCl}} \rightarrow \underset{\mathrm{Zinc}}{\mathrm{ZnCl}}+\frac{\mathrm{H}_{2}}{\text { Chloride }}+\text { Hydrogen gas }} \)

\( K ( SO _ { 3 } ) + HCl - SO _ { 2 } KCl + H _ { 2 } O \)

Provide the number of protons, electrons, and neutrons in the following neutral elements, isotopes, and ions. If the mass number isn't provided, use the mass number for the most common isotope of that element. 1. Iodine-135 2. Nitrogen-15

How many grams are there in each of the following samples? (convert mols to grams) a. 3 mols of Beryllium-9

In the year 2005 , a picture supposedly painted by a famous artist some time after 1715 but before 1765 contains 97.6 percent of its carbon-14 (half-life 5730 years). From this information, could this picture have been painted by this artist? ? Approximately how old is the painting? \( \square \) years