Posted by HELP on .
A 2.50-g sample of powdered zinc is added to 100.0 mL of a 2.00-M aqueous solution of hydrobromic acid in a calorimeter. The total heat capacity of the calorimeter and solution is 448 J/K. The observed increase in temperature is 21.1 K at a constant pressure of one bar. Using these data, calculate the standard enthalpy of reaction.
mols Zn = grams/molar mass = approximately 0.04 mol (but this is an estimate) and Zn is the limiting reagent.
Zn + 2HBr ==> H2 + ZnBr2
qrxn = Ccal x delta T.
qrxn/mol = [qrxn/mols Zn] = ?