Respuesta :
The question is incomplete, here is the complete question:
Use the following thermochemical equation to calculate how much heat in kilojoules is evolved or absorbed when 12.4 g of liquid water are converted to hydrogen and oxygen gas.
[tex]2H_2O(l)\rightarrow 2H_2(g)+O_2(g);\Delta H=571.6kJ[/tex]
Answer: The amount of heat absorbed for the given amount of water is 197.2 kJ
Explanation:
To calculate the number of moles, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Given mass of water = 12.4 g
Molar mass of water = 18 g/mol
Putting values in above equation, we get:
[tex]\text{Moles of water}=\frac{12.4g}{18g/mol}=0.69mol[/tex]
For the given chemical reaction:
[tex]2H_2O(l)\rightarrow 2H_2(g)+O_2(g);\Delta H=571.6kJ[/tex]
Enthalpy change of the reaction = 571.6 kJ
By Stoichiometry of the reaction:
For 2 moles of water, the amount of heat absorbed is 571.6 kJ
So, for 0.69 moles of water, the amount of heat absorbed will be = [tex]\frac{571.6}{2}\times 0.69=197.2kJ[/tex]
Hence, the amount of heat absorbed for the given amount of water is 197.2 kJ
