If the half-life of I-131 is 7.4 days, how many days would it take for only \( 3.2 \times \) \( 10^{-2} \) grams of \( 1-131 \) to be left in Mr. Miller's body if Dr. Goodie started him on an initial dose of 5.5 grams?

Son los coeficientes de la ecuación al balancerala por el método redox \( \mathrm{KMnO}_{4}+\mathrm{Zn}+\mathrm{H}_{2} \mathrm{SO}_{4} \xrightarrow{\mathrm{KHSO}_{4}+\mathrm{MnSO}_{4}+\mathrm{ZnSO}_{4}+\mathrm{H}_{2} \mathrm{O}} \) \( \begin{array}{llll}\text { a) } 2,5,9,2,2,5,8 & \text { b) } 8,2,5,9,2,2,5 & \text { c) } 5,8,2,5,8,2,2 & \text { d) } 2,5,8,2,5,8,2\end{array} \)

If the half-life of I-131 is 7.4 days, how many days would it take for only \( 3.2 \times \) \( 10^{-2} \) grams of \( 1-131 \) to be left in Mr. Miller's body if Dr. Goodie started him on an initial dose of 5.5 grams?

3) \( \mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}+\mathrm{KI}+\mathrm{KIO}_{3}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{Cr}(\mathrm{OH})_{3}+\mathrm{K}_{2} \mathrm{SO}_{4}+\mathrm{I}_{2} \) \( \begin{array}{l}\text { Semireacción de oxidación } \\ \text { Agente oxidante }\end{array} \)

En la ecuación al quedar balanceada, el coeficiente del agua es: \( \mathrm{KMnO}_{4}+\mathrm{NH}_{3} \xrightarrow{\mathrm{KNO}_{3}+\mathrm{MnO}_{2}+\mathrm{KOH}+\mathrm{H}_{2} \mathrm{O}} \) \( \begin{array}{llll}\text { a) } 2 & \text { b) } 3 & \text { c) } 8 & \text { d) } 5\end{array} \)

\( \mathrm{LiOH}+\mathrm{HBr} \rightarrow \mathrm{LiBr}+\mathrm{H}_{2} \mathrm{O} \) If you start with 10.0 grams of lithium hydroxide, how many grams of lithium bromide will be produced?