Hydrogen H2 is used as a rocker fuel. The hydrogen is burned in oxygen to produce water vapor.
2H2 + O2 ----> 2H2O
Delta H = -484 kJ
What is the enthalpy change per gram of hydrogen?
delta H for 2 mols is -484 kJ.
So delta H for 1 mol is what? -484/2 = ??
And a mol of H2 has a mass of 2 grams, so what is delta H for 1 gram?
To calculate the enthalpy change per gram of hydrogen, we need to use the given information of the enthalpy change for the reaction and the molar mass of hydrogen.
1. Start by calculating the moles of hydrogen used in the reaction. We know that the stoichiometric coefficient for hydrogen in the balanced equation is 2, meaning that 2 moles of hydrogen react with 1 mole of oxygen to produce 2 moles of water.
Since the balanced equation shows that 2 moles of H2 react, we can say that the enthalpy change for 2 moles of hydrogen is -484 kJ.
2. Next, calculate the moles of hydrogen in one mole of H2. The molar mass of hydrogen is approximately 2 g/mol, so one mole of hydrogen gas (H2) contains 2 grams of hydrogen.
Therefore, the enthalpy change for 1 mole of hydrogen is -484 kJ/2 = -242 kJ.
3. Finally, calculate the enthalpy change per gram of hydrogen. Since there are 2 grams of hydrogen in one mole of hydrogen, we can divide -242 kJ by 2 to get the enthalpy change per gram:
(-242 kJ) / (2 g) = -121 kJ/g
So, the enthalpy change per gram of hydrogen is approximately -121 kJ/g.