Asked Jun 12, 2019

When a chemist burns ammonia according to the reaction below she finds that the reaction releases heat. (It is exothermic.)

4NH3(g) + 3O2(g) 2N2(g) + 6H2O(g)

The enthalpy of the reaction DH = -1267 kJ. What is the enthalpy change (in kJ) when 3 grams of ammonia are burned? 


Expert Answer

Step 1

First, calculate the moles of ammonia by using its molar mass,


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mass Moles molarmass 3 GNH30.1761molNH3 17.031g/mol

Step 2

Now, calculate the en...


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Enthalpy change =(moles)x(AHof the reaction =(0.1761)-1267 kJ) =-223.12kJ.


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