Flame (fire) is the effect of a chemical reaction that produces visible light and heat. The chemical reaction is going on in the substance being burned.. Thats why coals glow and flames seem to leap into the air.
<span>If your reaction does not have a flame, then either it is not producing visible light or the reaction does not occur in the air above the substance.</span>
Answer:
The thermodynamic parameter which is of significance in this case is the 'Reduction Potential' for molecular bromine which is ~ +1.1 v vs N.H.E. In other words, it is a strong oxidizing agent. The bromine will oxidize sulfur compounds in which the valence of sulfur is lower than six to sulfate.
There are many possible reactions. Here is one possible example:
Na2 S2O3 + 4Br2 + 5 H2O = 2NaHSO4 + 8 HBr
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
Answer: Option (b) is the correct answer.
Explanation:
The elements which have excess or deficiency of electrons will react readily.
Atomic number of Mn is 25 and electronic configuration of
is [Ar]
. This configuration is stable.
Atomic number of Cr is 24 and electronic configuration of
is [Ar]
. This configuration is not stable.
Atomic number of Fe is 26 and electronic configuration of
is [Ar]
. This configuration is stable.
Atomic number of Cu is 29 and electronic configuration of
is [Ar]
. This configuration is not stable.
Atomic number of Al is 13 and electronic configuration of Al is
. This configuration is not stable.
Atomic number of Ba is 56 and electronic configuration of
is [Kr]
. This configuration is stable.
Atomic number of Mg is 12 and electronic configuration of
is
. This configuration is stable.
Atomic number of Sn is 50 and electronic configuration of Sn is [Kr]
. This configuration is stable.
Thus, we can conclude that out of the given options, only Fe and
reactants would lead to a spontaneous reaction as they have incomplete sub-shells. Therefore, in order to gain stability they will readily react.
In a carbohydrate, the ratio of hydrogen atoms to carbon atoms to oxygen atoms is:4:6:1