Given the balanced chemical equation: Ba(NO3)2(aq) + Na2SO4(aq) → BaSO4(s) + 2 NaNO3(aq)

A 0.4 L of 0.250 M Ba(NO3)2(aq) is mixed with excess Na2SO4(aq) to make 100.0 g of solution in a coffee-cup calorimeter and allowed to react completely. The temperature of the solution rises from 20.2 ºC to 26.4 ºC. Answer the question in each step to find ∆Hrxn for this reaction. Cs, soln = 4.18 J/g ºC

Step 1: The reaction is
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because the solution temperature increases. The heat absorbed by the solution (qsoln) is
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.

Step 2: The heat associated with the reaction (qrxn) is
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.

Step 3: Use qrxn and the stoichiometric relations in the balanced chemical equation to calculate ∆Hrxn. ∆Hrxn is
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.