Strontium-90 is a radioactive material that decays according to the function \( A(t)=A_{0} e^{-0.0244 t} \), where \( A_{0} \) is the initial amount present and \( A \) is the amount present at time \( t \) (in years). Assume that a scientist has a sample of 800 grams of strontium-90. (a) What is the decay rate of strontium-90? (b) How much strontium- 90 is left after 40 years? (c) When will only 200 grams of strontium-90 be left? (d) What is the half-life of strontium-90? (a) The decay rate of strontium- 90 is \( \square \% \). (Type an integer or a decimal. Include the negative sign for the decay rate.)

Types of Chemical Reactions \( \quad \) Which of the following is only produced by a double

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

If the half-life of I-131 is 10.4 days, how many moles of I-131 would be left in Mr. Miller's body after 47 days if he was infused with 7.2 grams? (Round your answer to four decimal places) 0.0117

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

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?