The formula for water is H2O so there would have to be two Hyrdogens and one oxygen. Therefore it would be 4g of Hydrogen and 16g of Oxygen leaving you with 20g.
The answer is D.
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The enthalpy of vaporization of H2O is higher than the enthalpy of fusion of H2O, therefore vaporizing the same mass of H2O would require more heat/energy than melting the same mass of H2O.
D, carbon dioxide and water. Methane and oxygen PRODUCE carbon dioxide and water in their reaction.
Answer : The heat of the reaction is -221.6 kJ
Explanation :
Heat released by the reaction = Heat absorbed by the calorimeter


where,
= heat released by the reaction = ?
= heat absorbed by the calorimeter
= specific heat of calorimeter = 
= change in temperature = 
Now put all the given values in the above formula, we get:


As, 
So, 
Thus, the heat of the reaction is -221.6 kJ