q = Ccal x delta T
dHrxn/g Zn = q/2.50
dHrxn/mol Zn = (q/2.50) x (atomic mass Zn/mol) = ?
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/°C. The observed increase in temperature is 21.1 °C at a constant pressure of one atm. Using these data, calculate the standard enthalpy of reaction.
2 answers
-247 KJ/mol