2H2+1O2=2H2O delta H=-136 kJ
A) how many joules are released when 35.0 grams H2O form
B)how many grams of hydrogen burn when 278 kJ are released.
C) Draw a potential energy diagram of this reaction.
a)
136 kJ released when 36 g H2O formed; therefore, 136 x 35/36 = ?kJ released for 35 g. Convert to J.
b)
136 kJ released when 4 g H burns. So
4 g H2 x 278/136 = ? g H burn when 278 kJ released.
A) To find the number of joules released when 35.0 grams of H2O forms, we need to use the given delta H value and the molar mass of water.
1. Convert the mass of H2O to moles:
Mass of H2O = 35.0 grams
Molar mass of H2O = 2(1.008 g/mol) + 16.00 g/mol = 18.02 g/mol
Number of moles of H2O = Mass of H2O / Molar mass of H2O
= 35.0 g / 18.02 g/mol
2. Calculate the energy released using the balanced chemical equation and the delta H value:
From the balanced equation: 2H2 + 1O2 -> 2H2O
The delta H value is -136 kJ for the formation of 2 moles of H2O.
Energy released per mole of H2O = delta H / 2 = -136 kJ / 2
3. Convert kJ to joules:
1 kJ = 1000 J
Therefore, the number of joules released when 35.0 grams of H2O form is:
Energy released = Energy released per mole of H2O * Number of moles of H2O * 1000 J
B) To find the number of grams of hydrogen that burn when 278 kJ are released, we need to use the given delta H value and the molar mass of hydrogen.
1. Convert kJ to joules:
1 kJ = 1000 J
Therefore, the number of joules released is:
Energy released = 278 kJ * 1000 J/kJ
2. Calculate the number of moles of H2 that correspond to this energy release using the balanced chemical equation and the delta H value:
From the balanced equation: 2H2 + 1O2 -> 2H2O
The delta H value is -136 kJ for the formation of 2 moles of H2O.
Energy released per mole of H2O = delta H / 2 = -136 kJ / 2
Number of moles of H2 = Energy released / Energy released per mole of H2O
3. Calculate the mass of H2 in grams:
Molar mass of H2 = 2(1.008 g/mol) = 2.016 g/mol
Mass of H2 = Number of moles of H2 * Molar mass of H2
C) Unfortunately, as a text-based AI, I am unable to draw diagrams. However, a potential energy diagram for this reaction would typically show the energy levels of reactants and products, as well as the activation energy required for the reaction to occur. The initial energy of the reactants will be higher than the final energy of the products, indicating that the reaction is exothermic.