Answer: 72.4 kJ/mol
Explanation:
The balanced chemical reaction is,
The expression for enthalpy change is,
![\Delta H=\sum [n\times \Delta H_f(product)]-\sum [n\times \Delta H_f(reactant)]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28product%29%5D-%5Csum%20%5Bn%5Ctimes%20%5CDelta%20H_f%28reactant%29%5D)
![\Delta H=[(n_{CO_2}\times \Delta H_{CO_2})+(n_{H_2O}\times \Delta H_{H_2O})]-[(n_{O_2}\times \Delta H_{O_2})+(n_{C_3H_8}\times \Delta H_{C_3H_8})]](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5B%28n_%7BCO_2%7D%5Ctimes%20%5CDelta%20H_%7BCO_2%7D%29%2B%28n_%7BH_2O%7D%5Ctimes%20%5CDelta%20H_%7BH_2O%7D%29%5D-%5B%28n_%7BO_2%7D%5Ctimes%20%5CDelta%20H_%7BO_2%7D%29%2B%28n_%7BC_3H_8%7D%5Ctimes%20%5CDelta%20H_%7BC_3H_8%7D%29%5D)
where,
n = number of moles
(as heat of formation of substances in their standard state is zero
Now put all the given values in this expression, we get
![-2220.1=[(3\times -393.5)+(4\times -241.8)]-[(5\times 0)+(1\times \Delta H_{C_3H_8})]](https://tex.z-dn.net/?f=-2220.1%3D%5B%283%5Ctimes%20-393.5%29%2B%284%5Ctimes%20-241.8%29%5D-%5B%285%5Ctimes%200%29%2B%281%5Ctimes%20%5CDelta%20H_%7BC_3H_8%7D%29%5D)
Therefore, the heat of formation of propane is 72.4 kJ/mol
<span>Based on solubilities you can separate naphthalene and NaCl by adding the mixture to a volume of water. NaCl is highly soluble in water, so it will dissolve completely, while the insoluble naphthalen will remain solid. Next your filter the solution, washing the solid with pure water to eliminate all the NaCl from it. The NaCl will remain is solution, and you can obtain it by evaporating the water. The other method to separate naphthalene and NaCl is based on sublimation property of naphthalene: you can permit that naphthalene sublimes freely or use vacuum to accelerate the process. You use a closed vessel to catch all the gas, while the NaCl will remain solid.</span>
Using the periodic table, the pair of non metals that has the most similar properties would be :
Oxygen and Selenium
at the periodic table, these both located on the same period
hope this helps
When electrons in atom interaction with light or photons one of the two process takes place:
1) they can absorb photons of a characteristic wavelength (which depends on the energy difference between two interacting atomic levels) and get excited to a higher energy level
2) or they can jump to a lower energy level and emit photons of the corresponding wavelength.
The type of spectrum produced when electrons in an atom undergo transitions to various levels by absorbing or emitting photons is termed as atomic spectrum.
The higher the temperature of the gas, the faster the molecules move as they approach evaporating temperature. The lower the temperature of the gas, the slower the molecules move as they approach cooling temperature. The temperature controls how fast the molecules move
