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be 5.0 mg/Ag body weight 4 The second-order rate constant for the decomposition

ID: 939396 • Letter: B

Question

be 5.0 mg/Ag body weight 4 The second-order rate constant for the decomposition of .8 Hi ar 750 °C was given in Problem 13.81. At2.5 × 103 minutes after a parcicular experiment had begun, the HI L-1. What concentration was equal to 4.5x 10 mol was the initial molar conceniration of HI in ther vessel? ar concentration of HI in the reaction .85 The half-life of a certain first-order reaction is 15 min e hlf-life of a certain first-order reaction is 15 min- utes. What fraction of the original reactant concentration will remain after 2.0 hours? 86 Strontium-90 has a half-life of 28 years. How long will it take for all of the strontium-90 presently on earth to b reduced to ,32 of its present amount? 87 Using the graph from Problem 13.53, determine th time required for the SO,Cl2 concentration to drop from 0.100 mol L- to 0.050 mol L-. How long does it tak for the concentration to drop from 0.050 mol L t 0.025 mol L-? What is the order of this reaction? (Hin How is the half-life related to concentration?) 38 Using the graph from Problem 13.54, determine ho long it takes for the CH,CHO concentration to decreas from 0.200 mol L to 0.100 mol L-1. How long does take the concentration to drop from 0.100 mol L 0.050 mol L-? What is the order of this reaction? (Hin

Explanation / Answer


K = (1/t)ln(a/x)

k = 0.693/15 = 0.0462 min-1.

0.0462 = (1/(2*60))ln(100/x)

x = 0.391 = concentration after 2 hr

fraction of reactant left = 0.391/100 = 0.00391


86.

K = 0.693/28 = 0.02475 yr-1.

0.02475 = (1/t)ln(1/(1/32))

t = 140.03 yr