Consider the following equation: CO + 2 H2 → CH3OH △H rxn = -128 kJ
Calculate the amount of heat (in kJ) associated with complete reaction of 8.08 g H2.
how would i set this up?
See it? You get 128 kJ for 4*1.01 g H. So how much will you get for 8.08?twice as much?
To calculate the amount of heat associated with the complete reaction of 8.08 g of H2, we need to use stoichiometry and the given equation's enthalpy change (∆Hrxn).
Step 1: Convert the mass of H2 to moles
To find the moles of H2, we need to use its molar mass. The molar mass of H2 is 2 g/mol.
Mass of H2 = 8.08 g
Molar mass of H2 = 2 g/mol
Moles of H2 = Mass of H2 / Molar mass of H2 = 8.08 g / 2 g/mol = 4.04 mol
Step 2: Determine the stoichiometric ratio
From the balanced equation, we see that 2 moles of H2 react with 1 mole of CH3OH. This means that the stoichiometric ratio between H2 and CH3OH is 2:1.
Step 3: Calculate the amount of heat
Using the stoichiometric ratio and the given enthalpy change, we can calculate the amount of heat associated with the complete reaction of 8.08 g of H2.
∆Hrxn = -128 kJ
Moles of H2 = 4.04 mol
∆Hrxn (per mol) = -128 kJ
∆Hrxn (total) = ∆Hrxn (per mol) × Moles of H2
∆Hrxn (total) = -128 kJ/mol × 4.04 mol
∆Hrxn (total) = -517.12 kJ
Therefore, the amount of heat associated with the complete reaction of 8.08 g of H2 is -517.12 kJ. Note: The negative sign indicates that the reaction is exothermic, releasing heat.
To calculate the amount of heat associated with the complete reaction of 8.08 g of H2, we need to follow these steps:
Step 1: Convert the mass of H2 into moles.
Step 2: Use the stoichiometry of the balanced equation to determine the moles of CH3OH produced.
Step 3: Calculate the heat absorbed or released per mole of CH3OH formed.
Step 4: Multiply the moles of CH3OH by the heat per mole value to get the total heat associated with the reaction.
Let's break down each step in detail:
Step 1: Convert the mass of H2 into moles.
The molar mass of H2 is 2 grams/mol, so we can use the formula:
moles = mass (in grams) / molar mass
In this case, moles of H2 = 8.08 g / 2 g/mol = 4.04 mol
Step 2: Use the stoichiometry of the balanced equation to determine the moles of CH3OH produced.
From the balanced equation, we can see that 2 moles of H2 produce 1 mole of CH3OH. Therefore, the moles of CH3OH produced will be half the moles of H2.
moles of CH3OH = 4.04 mol / 2 = 2.02 mol
Step 3: Calculate the heat absorbed or released per mole of CH3OH formed.
The heat of the reaction is given as △H rxn = -128 kJ, which represents the heat for 1 mole of CH3OH.
Therefore, the heat per mole of CH3OH formed is -128 kJ.
Step 4: Multiply the moles of CH3OH by the heat per mole value to get the total heat associated with the reaction.
Total heat = moles of CH3OH * heat per mole
Total heat = 2.02 mol * (-128 kJ/mol) = -258.56 kJ
Therefore, the amount of heat associated with the complete reaction of 8.08 g of H2 is -258.56 kJ. The negative sign indicates that the reaction releases heat.