Question

100.0 g of an aqueous solution containing lead nitrate and 100.0 g of an aqueous solution containing sodium iodide (both solutions at 22.6 C), are mixed in a calorimeterwith a heat capacity of 472 J/C.; thereactants undergo a metathesis reaction that raises thetemperature of the mixture to 24.2 C. Calculate the amount of heat generated by the reaction, correcting for the heat absorbed by the calorimeter and assuming that the specific heat of the reaction solution is the same as water.

Answer 1

m = 100 g of sample Pb(NO3)2

m = 100 g of sample NaI

Ti = 22.6°C

C = 474 J/gC

Tf = 24.2°C

find Q generated

a)

First, identify total mass of solution

m = 100 g + 100 = 200 g of solution

C = 4.184 J/gC

The heat equation for calorimter

Qcalorimter = Ccal*dT = 472 * (24.2-22.6 ) = 755.2 J are absorbed by the calorimter

Qsolutions = mtotal * Csolutoin * (Tf-Ti) = 200*4.184*(24.2-22.6 ) = 1338.88 J absorbed

Therefore, for the reaction

Qreaction = -Qabsorbed

Qreaction = Qcal + Qsoln = 755.2 + 1338.88 =

Qreaction = -2094.08 J

Qrxn = -2.094 kJ

answered by: anonymous