I need these done please

Given the following at 25C calculate delta Hf for HCN (g) at 25C. 2NH3 (g) +3O2 (g) + 2CH4 (g) ---> 2HCN (g) + 6H2O (g) delta

AysviL [449]

Answer: The $\Delta H_f$ for HCN (g) in the reaction is 135.1 kJ/mol.

Explanation:

Enthalpy change is defined as the difference in enthalpies of all the product and the reactants each multiplied with their respective number of moles. The equation used to calculate enthalpy change is of a reaction is:

$\Delta H_{rxn}=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]$

For the given chemical reaction:

$2NH_3(g)+3O_2(g)+2CH_4(g)\rightarrow 2HCN(g)+6H_2O(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H_{rxn}=[(2\times \Delta H_f_{(HCN)})+(6\times \Delta H_f_{(H_2O)})]-[(2\times \Delta H_f_{(NH_3)})+(3\times \Delta H_f_{(O_2)})+(2\times \Delta H_f_{(CH_4)})]$

We are given:

$\Delta H_f_{(H_2O)}=-241.8kJ/mol\\\Delta H_f_{(NH_3)}=-80.3kJ/mol\\\Delta H_f_{(CH_4)}=-74.6kJ/mol\\\Delta H_f_{(O_2)}=0kJ/mol\\\Delta H_{rxn}=-870.8kJ$

Putting values in above equation, we get:

$-870.8=[(2\times \Delta H_f_{(HCN)})+(6\times (-241.8))]-[(2\times (-80.3))+(3\times (0))+(2\times (-74.6))]\\\\\Delta H_f_{(HCN)}=135.1kJ$

Hence, the $\Delta H_f$ for HCN (g) in the reaction is 135.1 kJ/mol.

8 0

3 years ago

Silicon is an element that is found directly underneath carbon in the periodic table and thus has similar properties to carbon,

kirza4 [7]

Answer:

Four electrons are present in the valence shell of Silicon.

Explanation:

Valence shell electrons are those electrons which are present in the outermost shell of an atom. These valence shell electrons are responsible for in the formation of bonds with other atoms.

Silicon having atomic number 14 has fourteen electrons in its neutral state and has the electronic configuration as follow;

1s², 2s², 2p⁶, 3s², 3p²

In given configuration the valence shell (outermost shell) is 3 and the number of electrons present in it are four i.e. 3s² and 3p² (2 + 2 = 4) respectively.

7 0

3 years ago

For each of the bonds listed, tell which atom is more negatively charged a. C--H b. C--N c. C--S d. C--O

blondinia [14]

Explanation:

The atom is considered to be more electronegative , when it has the tendency to get a slight negative i.e. , delta negative charge on it , and the other atom gets a delta positive charge .

In the periodic table ,

As we go left to right in the periodic table , the electronegativity increases ,

and

As we go top to bottom , the electronegativity decreases .

Hence , from the option given in the question ,

a. C--H , the electronegativity of both the atom is almost the same , but looking at the treads of the periodic table , Carbon is more electronegative than hydrogen .

b. C--N , the electronegativity of both the atom is almost the same , but looking at the treads of the periodic table , nitrogen is more electronegative than Carbon .

c. C--S , the electronegativity of both the atom is almost the same , but looking at the treads of the periodic table , sulfur is more electronegative than Carbon .

d. C--O , the electronegativity of both the atom is almost the same , but looking at the treads of the periodic table , oxygen is more electronegative than Carbon .

5 0

3 years ago

What causes acid rain is it hydroelectric energy is it fossil fuels or is it geothermal energy

Vladimir79 [104]

Hydroelectric energy is best answer

5 0

3 years ago

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The diagram above shows the atomic emission line spectrum of hydrogen. The wavelength of each line is shown at the top of the li

Anni [7]

Hello there,

Your correct answer would be "the energy of a photon".

Hope this helps.

~Hottwizzlers

6 0

3 years ago

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