<u>Answer:</u> The enthalpy of formation of HCN(g) is 135.1 kJ/mol
<u>Explanation:</u>
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:
For the given chemical reaction:
The equation for the enthalpy change of the above reaction is:
We are given:
Putting values in above equation, we get:
Hence, the enthalpy of formation of HCN(g) is 135.1 kJ/mol
Answer:
Wt Avg Atomic Wt = 28.0577 amu
Explanation:
Atomic Mass = ∑Wt Avg contributions of isotopes of an element
Si-28 => 92.21% => 0.9221 decimal fraction => Wt Avg Si-28 = 0.9221(27.9769) = 25.7695 amu
Si-29 => 4.69% => 0.0469 decimal fraction => Wt Avg Si-29 = 0.0469(28.9765) = 1.3590 amu
Si-30 => 3.10% => 0.0310 decimal fraction => Wt Avg Si-30 = 0.0310(29.9737) = 0.9292
Wt Avg Atomic Wt = ∑Wt Avg Contributions = (25.7695 + 1.3590 + 0.9292)amu = 28.0577 amu
Brass is an example of homogeneous mixture.