Given 1.01 g of H2 in the reaction H2 + 1/2 O2 = H2O. The Delta H for solution is 143 kJ. What is the delta H for the reaction?
I'm confused by the term "solution". If the standard rxn dH is 143 kJ/mol it is done this way:
dHrxn = 143 kJ x (1.01/molar mass H2) = ?
To calculate the ΔH for the reaction, we need to use the stoichiometric coefficients of the balanced equation and the given ΔH for the solution.
The balanced equation is:
H2 + 1/2 O2 → H2O
From the balanced equation, we can see that one mole of H2 reacts with 1/2 mole of O2 to form one mole of H2O.
Given that 1.01 g of H2 is involved in the reaction, we need to convert this mass into moles using the molar mass of H2.
The molar mass of H2 is 2 g/mol (2 atomic mass units).
Using the given mass of 1.01 g and the molar mass of H2 (2 g/mol):
n(H2) = m(H2) / M(H2)
= 1.01 g / 2 g/mol
= 0.505 mol
Now, we read the stoichiometric coefficient of ΔH from the balanced equation:
ΔH = 143 kJ (given in the problem)
Since ΔH is given for the reaction per mole of H2, we need to multiply ΔH by the number of moles of H2 involved in the reaction:
ΔH_reaction = ΔH_solution x n(H2)
= 143 kJ/mol x 0.505 mol
= 72.215 kJ
Therefore, the ΔH for the reaction is approximately 72.215 kJ.
To determine the ΔH (enthalpy change) for the reaction H2 + 1/2 O2 → H2O using the given quantity of H2 (1.01 g) and the ΔH value (143 kJ), we need to use the molar masses and stoichiometry of the reaction.
Here are the steps to calculate ΔH for the reaction:
Step 1: Convert the given mass of H2 to moles.
First, we need to calculate the number of moles of H2 by using its molar mass. The molar mass of H2 is approximately 2 g/mol. We can use this information and the given mass to determine the number of moles of H2.
Moles of H2 = Given mass / Molar mass = 1.01 g / 2 g/mol
Step 2: Identify the stoichiometric coefficients.
From the balanced equation H2 + 1/2 O2 → H2O, we can see that 1 mole of H2 reacts with 1/2 mole of O2 to produce 1 mole of H2O. This means the stoichiometric coefficient of H2 is 1.
Step 3: Calculate ΔH for the reaction.
Since the ΔH value given is for the molar amount of H2 (1 mole), we can directly use it to determine ΔH for the reaction. If, in the given reaction, 1 mole of H2 releases 143 kJ of energy, then we can conclude that the ΔH for the reaction is also 143 kJ.
Therefore, the ΔH for the reaction H2 + 1/2 O2 → H2O, using 1.01 g of H2, is 143 kJ.