Two parallel pipelines spaced 0.5 m apart are buried in soil having a thermal conductivity of 0.5 w/m·k. the pipes have outer diameters of 70.0 and 52.5 mm with surface temperatures of 175°c and 5°c, respectively. estimate the heat transfer rate per unit length between the two pipelines.

Answerchemical energy;

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Idon’t really understand the question i’m sorry i can’t

Reaction involved in present system is :   c12h22o11 + h2o → 2 c6h12o6the reaction system is obeying following rate law:   rate = k[c12h22o11]thus, it is a first order reaction.now, for 1st order reactionrate constant (k) =  given: initial conc. = 3.0 g, final conc. = 2.7 g, t = 2.5 h∴rate constant (k) =  ∴ k = 0.04215 h-1now, for 1st order reaction, half life = 0.693/k = 0.693/0.04215 = 16.4 hthus correct answer is option b