relating the half-life of a second- order reaction to the rate constant. How does it differ from the equation for a first-order reaction? 13.24 For a first-order reaction, how long will it take for the concentration of reactant to fall to one-eighth its original value? Express your answer in terms of the half-life (t) and in terms of the rate constant k. 1. Problems 13.25 ) What is the half-life of a compound if 75 percent of a given sample of the compound decomposes in 60min? Assume first-order kinetics. 13 13 13.26 The thermal decomposition of phosphine (PH3) into 13 phosphorus and molecular hydrogen is a first-order reaction: 4PH3(g) → P4(g) + 6H2(g) 13 The half-life of the reaction is 35.0 s at 680°C. Cal- culate (a) the first-order rate constant for the reac- tion and (b) the time required for 95 percent of the phosphine to decompose. 13 13.27/ The rate constant for the second-order reaction 2NOBr(g) 2NO(g) + Br2(g) -> is 0.80/M s at 10°C. (a) Starting with a concentra- tion of 0.086 M, calculate the concentration of NOBr after 22 s. (b) Calculate the half-lives when [NOBR]o =0.072 M and [NOBR]o = 0.054 M. 13 %3D %3D 13.28 The rate constant for the second-order reaction Pr 2NO2(g) 2NO(g) + O2(8) is 0 54/AA

mol (5.77. Miners' Lamps Before the development of reliable batteries, miners' lamps burned acetylene (C₂H₂) produced by the reaction of calcium carbide with water: Sang Irobin CaC₂(s) + H₂O(l) → C₂H₂(g) + CaO(s) ng hl A lamp uses 1.00 L of acetylene per hour at 1.00 atm pressure and 18°C. a. How many moles of C₂H₂ are used per hour? SI b. How many grams of calcium carbide must be in the lamp for a 4-h shift? 915 is to colo

Animal fat or vegetable oils (triacylglycerides) can be broken down into glycerol and the sodium salts of the carboxylic acids using NaOH. What is this process called? saponification O trituration O dissolution esterification

Aa.17.