Numerade

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Problem 13 The activities of $^{131}$I and $^{123}$I used in thyroid scans are measured to be 50 and 70 $\mu$Ci, respectively. Find and compare the masses of $^{131}$I and $^{123}$I in such scans, given their respective half-lives are 8.04days and 13.2hours. The masses are so small that the radioiodine is usually mixed with stable iodine as a carrier to ensure normal chemistry and distribution in the body. (Data: M($^{131}$I) = 130.91g/mol; t$_{1/2}$($^{131}$I) = 8.04days; M($^{123}$I) = 122.91g/mol; t$_{1/2}$($^{123}$I) = 13.2 hours)(5pt) $m_{131}$ = $m_{123}$ =

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Suppose that exchange rate between the dollar and the peso is in equilibrium when inflation in the U.S. rises to 2.00%. At the same time, inflation in Mexico is 7.00%. If the inflation rate in the U.S. is denoted as IhIh and the inflation rate in Mexico is IfIf, then which of the following expressions represents the percent change in the peso under PPP? 1+Ih1+If+11+Ih1+If+1 1+Ih1+If−11+Ih1+If−1 1+If1+Ih+11+If1+Ih+1 1+If1+Ih−11+If1+Ih−1 According to this formula, percentage change in the peso should be under PPP.

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This question deals with a precipitation titration of the relatively insoluble salt AB2 (s), for which Ksp is 1.00 \times 10-20. The analyte flask contains A+2 at an initial concentration of [A+2]initial = 0.1000 M and an initial volume of Vinitial = 10.00 mL. The titrant in the buret contains B- at a concentration of 0.1000 M. What is the equivalence volume Veq? Group of answer choices Veq = 20.00 mL Veq = 5.00 mL Veq = 30.00 mL Veq = 10.00 mL

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Perform the following number system conversions: a. (253)6 = (?)10 b. (AB12 DE84)16 = (?)2 c. (1101 0111)2 = (?)16 d. (AB12 DE84)16 = (?)10 e. (387)10 = (?)2 f. (1001 0010 1101)2 = (?)10

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When an explanation for a phenomenon has been thoroughly tested and confirmed and generally accepted as true, in the scientific community this constitutes a A testable hypothesis B scientific theory C scientific law D scientific principle

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You just had a great lunch at a nice restaurant and decide to leave a 15% tip on your $18 meal. What will be the total charge on your debit card? Multiple Choice O O $33.00 $19.60 $21.60 $20.70

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a. Which one of these metals (Ag(s), Mg(s), Zn(s), Cu(s), or Pb(s)) or metal ions (Ag$^+$(aq), Mg$^{2+}$(aq), Zn$^{2+}$(aq), Cu$^{2+}$(aq), or Pb$^{2+}$(aq)) is the easiest to reduce? Make sure to include the physical state and the charge if it is an ion. Explain! b. Is this metal or metal ion a better oxidizing or reducing agent? Explain!

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Find the Fourier series of the function f on the given interval.\\ $f(x) = \begin{cases} \pi^2, & -\pi < x < 0\\ \pi^2 - x^2, & 0 \le x < \pi \end{cases}$\\ a. $f(x) = \frac{5\pi^2}{6} + \sum_{n=1}^{\infty} \left[ \frac{2}{n^2} \cos nx + \left( \frac{\pi}{n} + \frac{2[1-(-1)^n]}{n^3\pi} \right) \sin nx \right]$\\ b. $f(x) = \sum_{n=1}^{\infty} \left[ \frac{2}{n^2} \cos nx + \left( \frac{\pi}{n} + \frac{2[1-(-1)^n]}{n^3\pi} \right) \sin nx \right]$\\ c. $f(x) = \frac{5\pi^2}{6} + \sum_{n=1}^{\infty} \left[ \frac{2}{n^2}(-1)^{n+1} \cos nx + \left( \frac{\pi}{n}(-1)^n + \frac{2[1-(-1)^n]}{n^3\pi} \right) \sin nx \right]$\\ d. $f(x) = \frac{5\pi^2}{6} + \sum_{n=1}^{\infty} \left[ \frac{-2}{n^2} \cos nx + \left( \frac{\pi}{n} + \frac{2[1+(-1)^n]}{n^3\pi} \right) \sin nx \right]$

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Use the method of variation of parameters to solve the initial value problem x' = Ax + f(t), x(a) = xa using the following values. \begin{equation*} A = \begin{bmatrix} 3 & -1 \\ 9 & -3 \end{bmatrix}, \quad f(t) = \begin{bmatrix} 6 \\ 8 \end{bmatrix}, \quad x(0) = \begin{bmatrix} 2 \\ 4 \end{bmatrix}, \quad e^{At} = \begin{bmatrix} 1+3t & -t \\ 9t & 1-3t \end{bmatrix} \end{equation*} x(t) =

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A farmer sells corn futures contracts at a price of $2.75 per bushel. The spot price of corn is $2.55 at contract expiration. The farmer harvested 12,500 bushels of corn and sold futures contracts on 10,000 bushels of corn. What are the farmer's proceeds from the sale of corn? A. $27,500 B. $31,750 C. $33,875 D. $35,950

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