Hydrogen H2, is used asa 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.

To find the enthalpy change per gram of hydrogen, we need to calculate the enthalpy change (ΔH) and then divide it by the molar mass of hydrogen.

Given that the equation states that 2 moles of H2 are reacting, we can assume that the enthalpy change (-484 kJ) refers to 2 moles of hydrogen.

The molar mass of hydrogen (H2) is 2 grams per mole (2 g/mol).

To calculate the enthalpy change per gram of hydrogen, we can follow these steps:

Step 1: Calculate the moles of hydrogen (H2) using the molar mass and the number of grams of hydrogen. Since we have 2 moles of hydrogen, this step is not required.

Step 2: Divide the enthalpy change (-484 kJ) by the number of moles of hydrogen (2 moles).

ΔH per mole of hydrogen = (-484 kJ/ 2 moles) = -242 kJ/mol

Step 3: Divide the enthalpy change per mole of hydrogen by the molar mass of hydrogen (2 g/mol) to get the enthalpy change per gram of hydrogen.

ΔH per gram of hydrogen = (-242 kJ/mol) / (2 g/mol) = -121 kJ/g

Therefore, the enthalpy change per gram of hydrogen is -121 kJ/g.

Worked like the last problem.