4.15

[Jake Matsumoto 3E]

Could someone explain to me how they solved 4.15 in the textbook? Particularly, I would like to know the process of determining what equation to use and how to set it up. Thanks!

[Dexton Ratchford 2F]

They determined the limiting reactant using stoichiometry and moles and then derived the reaction enthalpy from the enthalpies of formation. The limiting reactant was found to be since and there were 0.13 mols (8.5g/ Zn Molar mass) present. they multiplied this value by the reaction enthalpy to get the energy released by the 8.5 grams of zinc. this value was about -20kj. Since this heat is what is used to heat our water we can set -20kj as our q in q=m c delta t and derive a value for delta t. The value of delta t ends up being about 6 degrees. adding this to our Ti of 25 degrees gives us our final temp of 31 degrees C.