Nobelium-259 is a radioactive substance that decays according to the following function, where \( y_{0} \) is the initial amount present, and \( y \) is the amount present at time \( t \) (in minutes). \[ y=y_{0} e^{-0.0119 t} \] Find the half-life of Nobelium-259. Do not round any intermediate computations, and round your answer to the nearest tenth.

The pH value is an expression of the molarity of \( \mathrm{H}_{3} \mathrm{O}^{+} \)ions in solution. This concentration has strong impact on chemical reactions. The molarity is very small value, and therefore awkward to use. The pH scale simplifies this concentration making communication easier and faster. Demonstrate the relationship between pH and \( \mathrm{H}_{3} \mathrm{O}^{+} \)molarity, using the formula, \( \mathrm{pH}=-\log \left(\mathrm{H}_{3} \mathrm{O}^{+}\right) \) where () indicates concentration in molarity of a substance. What is the pH of a solution, having the \( \mathrm{H}_{3} \mathrm{O}^{+} \)concentration of 0.000491 M ? Add your answer

You can also do the reverse, calculate the \( \mathrm{H}_{3} \mathrm{O}^{+} \)molarity from the pH , using the formula \( \mathrm{H}_{3} \mathrm{O}^{+} \)molarity \( =10^{-}-\mathrm{pH} \) What is the \( \mathrm{H}_{3} \mathrm{O}^{+} \)molarity of a solution having the pH of 2.56 ?

Este documento contiene entradas de lápiz, formas e imágenes que no son legibles en la vista para dispositi... \begin{tabular}{|l|l|l|l} 1. \( 2 p \) CONVERSIONES: Un hospital compra un frasco de alcohol isopropílico de 650 ml a \( \mathrm{S} / 0,60 \) para desinfección. Si la densidad del \\ alcohol es \( 0,75 \mathrm{~g} / \mathrm{cm}^{3} \) a temperatura ambiente, ¿cuál es el precio del alcohol por kilogramo? Equivalencia: \( 10^{3} \mathrm{~g}=1 \mathrm{~kg} \)\end{tabular}

1. Considere la evaporación de agua liquida para formar vapor a 1 atm de presion. a) ¿Est proceso es endotérrico oxotêrmico? b) ¿En cué intervalo de temperatura el proceso es espontaneo c) ¿En qué intervalo de temperatura es un proceso no espontàneo? d) ¿A qué temperaura las dos fases estàn en equilibrio?

Homework Questions Content Question 1 Using principles of molecular orbital theory, how many unpaired electrons are in each of the following molecules? NO \( { }^{+} \)Blank 1 NO Blank 2 BC Blank 3 BeC Blank 4