Reaction 2: C (s, graphite) + 2H2 (g) --> CH4 (g) Change in enthalply: -74.9 kJ/mol
Reaction 3: H2 (g) + 2C (s, graphite) + N2 (g) --> 2HCN (g) Change in enthalpy: +270.3 kJ/mol
Include the following:
The numerical answer with correct units.
State which reactions, if any, you had to "Flip".
State which reactions you had to multiply, if any, to get the correct amount of the compound.
The enthalpy for the reaction, ΔH rxn is 255.95 kJ/mol
From the question,
We are to calculate the change in enthalpy for the reaction
CH₄(g) + NH₃(g) → HCN(g) +3H₂(g)
From the given reactions
Reaction 1: N₂(g) + 3H₂(g) → 2NH₃(g) Change in enthalpy: -91.8 kJ/mol
Reaction 2: C(s, graphite) + 2H₂(g) → CH₄(g) Change in enthalply: -74.9 kJ/mol
Reaction 3: H₂(g) +2C(s, graphite) +N₂(g) → 2HCN (g) Change in enthalpy: +270.3 kJ/mol
First, flip reactions 1 and 2 to get reaction 4 and 5 respectively
Reaction 4: 2NH₃(g) → N₂(g) + 3H₂(g) ΔHo : 91.8 kJ/mol
Reaction 5: CH₄(g) → C(s, graphite) + 2H₂(g) ΔHo : 74.9 kJ/mol
Now, multiply reactions 4 and 3 by half (1/2) to get 6 and 7 respectively
Reaction 6: NH₃(g) → ¹/₂N₂(g) + ³/₂H₂(g) ΔHo : 45.9 kJ/mol
Reaction 7: ¹/₂H₂(g) +C(s, graphite) +¹/₂N₂(g) → HCN (g) ΔHo : +135.15 kJ/mol
Now,
Add reactions 5, 6, and 7 together
Reaction 5: CH₄(g) → C(s, graphite) + 2H₂(g) ΔHo : 74.9 kJ/mol
Reaction 6: NH₃(g) → ¹/₂N₂(g) + ³/₂H₂(g) ΔHo : 45.9 kJ/mol
Reaction 7: ¹/₂H₂(g) +C(s, graphite) +¹/₂N₂(g) → HCN(g) ΔHo : +135.15 kJ/mol
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CH₄(g) + NH₃(g) → HCN(g) + 3H₂(g) ΔH rxn = 255.95 kJ/mol
Hence, the enthalpy for the reaction, ΔH rxn is 255.95 kJ/mol
Learn more here: brainly.com/question/13779366
Answer:
255.8 kj/mol
Explanation:
So this is a Hess' Law problem, the CH₄ (g) + NH₃ (g) --> HCN (g) + 3H₂ (g) is what we want the other reactions to reflect. I usually set up problems like these like this in order to determine which reaction needs a coefficient change:
N₂ + 3H₂ --> 2NH₃ (ΔH=-91.8)
C + 2H₂ --> CH₄ (ΔH=-74.9
H₂ + 2C + N₂ --> 2HCN (ΔH=270.3)
CH₄ + NH₃ --> HCN + 3H₂
(I left out the states because it'll make the math easier) So, we want things to cancel out, meaning some of the reactants and products need to change places in order to do so. For the first reaction, we'd want to multiply the coefficients by in order to have it cancel out with the other reactions. For the third reaction, we'd want to we'd want to switch the products/reactants and multiply the coefficients by . Keep in mind whatever we do to the equation, we do to the ΔH. Should look like:
N₂ + H₂ --> NH₃ (ΔH=-45.9)
C + 2H₂ --> CH₄ (ΔH=-74.9)
HCN --> H₂ + C + N₂ (ΔH=-135)
CH₄ + NH₃ --> HCN + 3H₂
Everything cancels, so that means we can add all the ΔH, which should be -255.8 kj/mol, but we also change the sign in order to reflect what's happening in the reaction. (Sorry this is so long)
The yellow element that stinks when burned is sulfur.
Sulfur is a chemical element with the symbol S and atomic number 16. It is a non-metal that is a member of the chalcogen group in the periodic table. Sulfur is a yellow solid at room temperature. It is insoluble in water but soluble in carbon disulfide. When sulfur is burned, it produces a foul-smelling gas called sulfur dioxide.
Sulfur dioxide is a colorless gas with a pungent, irritating odor. It is a major air pollutant and can cause respiratory problems. Sulfur is used in a variety of applications, including the production of sulfuric acid, gunpowder, and rubber. It is also used in the vulcanization of rubber. Sulfur dioxide is a highly reactive gas. Sulfur dioxide has a low boiling point. Sulfur dioxide is heavier than air.
To know more about the Element, here
#SPJ6
B) Rb
C) Cl^{-}
D) Kr
O₂
CaCO₃
Ca(OH)₂
Which among the following will make lime water look milky
option C) Ca(OH)₂
Answer:
2.7*10^23
Explanation:
first work out the moles
So do 36g / 80 (80 is bromine's relative Atomic Mass number)
You have 0.45 M
Then, do 0.45 * 6.02*10^23
You get 2.7*10^23, which is your answer