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

Which of the following element combinations will likely form polyatomic ions? oxygen and carbon cesium and chlorine sodium and bromine xenon and neon

4. How many atoms are found in a 15.3 g sample of bismuth? A. \( 1.26 \times 10^{26} \) atoms B. \( 4.41 \times 10^{22} \) atoms C. \( 6.02 \times 10^{23} \) atoms D. \( 9.21 \times 10^{24} \) atoms

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

How many mols are there in each of the following samples? (convert grams to mols) a. 42 grams of the radioactive isotope Carbon-14

The half-life of Palladium-100 is 4 days. After 20 days a sample of Palladium-100 has been reduced to a mass of 1 mg . What was the initial mass (in mg ) of the sample? What is the mass 8 weeks after the start?