Question 1 From your calculations, which reaction experiment had closest to stoichiometric quantities? How many moles of \( \mathrm{NaHCO}_{3} \) and \( \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2} \) were present in this reaction?

Sunscreens contain compounds such as oxybenzone that absorb UV light. \( \quad \) Identify the functional groups in oxybenzone.

3. Para las reacciones redox completas que se muestran a continuación: a) divida cada reacción en sus semirreacciones; b) identifique el agente oxidante; c) identifique el agente reductor. a) \( 2 \mathrm{Sr}+\mathrm{O}_{2} \rightarrow 2 \mathrm{SrO} \) b) \( 2 \mathrm{Li}+\mathrm{H}_{2} \rightarrow 2 \mathrm{LiH} \) c) \( 2 \mathrm{Cs}+\mathrm{Br}_{2} \rightarrow 2 \mathrm{CsBr} \) d) \( 3 \mathrm{Mg}+\mathrm{N}_{2} \rightarrow \mathrm{Mg}_{3} \mathrm{~N}_{2} \) e) \( 4 \mathrm{Fe}+3 \mathrm{O}_{2} \rightarrow 2 \mathrm{Fe}_{2} \mathrm{O}_{3} \) f) \( \mathrm{Cl}+2 \mathrm{NaBr}_{2} \rightarrow 2 \mathrm{NaCl}+\mathrm{Br}_{2} \) g) \( \mathrm{Si}+2 \mathrm{~F}_{2} \rightarrow \mathrm{SiF}_{4} \) h) \( \mathrm{H}_{2}+\mathrm{Cl}_{2} \rightarrow 2 \mathrm{HCl} \)

Calculate the density of a cup of tap water at room temperature with a mass of 50.8 g and a volume of 52.1 mL . Round your answer to the appropriate number of sig figs. \( 0.975 \mathrm{~g} / \mathrm{mL} \) \( 1.0 \mathrm{~mL} / \mathrm{g} \)

From your calculations, which reaction experiment had closest to stoichiometric quantities? How mar moles of \( \mathrm{NaHCO}_{3} \) and \( \mathrm{HC}_{2} \mathrm{H}_{3} \mathrm{O}_{2} \) were present in this reaction?

Question 12 (1 point) \( \begin{array}{l}\text { 4) Listen } \\ \text { Medium carbon steel has a carbon content of } 0.35 \% \text {. What is the fractional portion } \\ \text { of carbon in this steel? }\end{array} \).