Standard enthalpy change of reaction.

https://www.youtube.com/watch?v=yhT8-Nm1-gk

6.54 g of zinc was added to 200 cm ³ of silver nitrate solution with concentration of 2 mol dm^-3

Correcting for cooling, the temperature was increased by 42 degrees C

Calculate standard enthalpy change of reaction.

In this reaction, silver nitrate is excess reagent.

First calculate heat energy released by reaction, use the equation q = mc delta T.'

so 200 × 4.18 × 42 = 35112 J = 35.112 kJ

We need to divide heat energy by number of moles of zinc

6.54g / 65.4 gmol-1 = 0.1 moles of zinc in our reaction.

So 35.112 kJ / 0.1 mol = -3511.12kJ mol-1. It is exothermic, so it needs a negative sign.

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