The thermochemical equation is the chemical equation including the net change of enthalpy (heat).
The chemical equation for the decomposition of methanol to form methane and oxygen is:
2CH3OH --> 2CH4 + O2
The thermochemical equation is:
2CH3OH ---> 2CH4 + O2 - 252.8 kJ
Note that the heat is placed as negative at the right side because it is absorbed during the decomposition, so the environment will have 252.8 kJ less per each mole of O2 produced.
You can equivalently write:
2CH3OH + 252.8 kJ --> 2CH4 + O2
Answer:
The value of Kc for the reaction is 3.24
Explanation:
A reversible chemical reaction, indicated by a double arrow, occurs in both directions: reagents transforming into products (
direct reaction) and products transforming back into reagents (inverse reaction)
Chemical Equilibrium is the state in which direct and indirect reactions have the same reaction rate. Then taking into account the rate constant of a direct reaction and its inverse the chemical constant Kc is defined.
Being:
aA + bB ⇔ cC + dD
where a, b, c and d are the stoichiometric coefficients, the equilibrium constant with the following equation:
![Kc=\frac{[C]^{c} *[D]^{d} }{[A]^{a} *[B]^{b} }](https://tex.z-dn.net/?f=Kc%3D%5Cfrac%7B%5BC%5D%5E%7Bc%7D%20%2A%5BD%5D%5E%7Bd%7D%20%7D%7B%5BA%5D%5E%7Ba%7D%20%2A%5BB%5D%5E%7Bb%7D%20%7D)
Kc is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients divided by the multiplication of the concentrations of the reagents also raised to their stoichiometric coefficients.
Then, in the reaction 3A(g) + 2B(g) ⇔ 2C(g), the constant Kc is:
![Kc=\frac{[C]^{2} }{[A]^{3} *[B]^{2} }](https://tex.z-dn.net/?f=Kc%3D%5Cfrac%7B%5BC%5D%5E%7B2%7D%20%7D%7B%5BA%5D%5E%7B3%7D%20%2A%5BB%5D%5E%7B2%7D%20%7D)
where:
- [A]= 0.855 M
- [B]= 1.23 M
- [C]= 1.75 M
Replacing:
![Kc=\frac{1.75^{2} }{0.855^{3}*1.23^{2} }](https://tex.z-dn.net/?f=Kc%3D%5Cfrac%7B1.75%5E%7B2%7D%20%7D%7B0.855%5E%7B3%7D%2A1.23%5E%7B2%7D%20%20%7D)
Solving you get:
Kc=3.24
<u><em>The value of Kc for the reaction is 3.24</em></u>
Answer:
gold wire (Au)
Explanation:
A substance that cannot be separated or broken down into simpler substances by chemical means is an element.
Between the given options only gold wire is an element, Au.
A way of knowing that it is an element is noticing that its formula is a single symbol which corresponds to an element found in the periodic table, unlike a combination of said symbols (like NaCl or H₂O).
Answer:
Explanation:
A reactant is a substance that is present at the start of a chemical reaction. The substance(s) to the right of the arrow are called products . A product is a substance that is present at the end of a chemical reaction.
h2 + 02 = h2o
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