All of the above. Halogens are extremely reactive. Their valency is -1 as they have 7 outer shell electrins and need 1 more to make it 8. They also react with metals to form salt. So the ans is (D)
1. The conjugate acid-base pairs are HCl/Cl- and NH3/NH4+. They can be changed into one another by proton transfer.
2. The acid in the reaction is the molecule that has the lowest pKa value or (simply) gives their proton away the easiest. The pKa of HCl is around 3 I think while ammonia’s is around 35. This means HCl is the acid here. In the other reaction (backwards) you can see that NH4+ gives a proton to the chloride ion. To give a proton = acid. So the acids are HCl and NH4+ and the bases are NH3 and Cl-.
An important rule is: The stronger the acid/base, the weaker its conjugate base/acid.
Answer: 48.6 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_6H_6}\times \Delta H_{C_6H_6})]](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_6H_6%7D%5Ctimes%20%5CDelta%20H_%7BC_6H_6%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
![-6534.0=[(12\times -393.5)+(6\times -285.8)]-[(15\times 0)+(2\times \Delta H_{C_6H_6})]](https://tex.z-dn.net/?f=-6534.0%3D%5B%2812%5Ctimes%20-393.5%29%2B%286%5Ctimes%20-285.8%29%5D-%5B%2815%5Ctimes%200%29%2B%282%5Ctimes%20%5CDelta%20H_%7BC_6H_6%7D%29%5D)
Therefore, the enthalpy change for benzene is 48.6 kJ/mol
Answer:
B
Explanation:
The reaction will occur naturally
To find out how many molecules you have, you need to multiply the number of moles with Avogadros constant: 2.50 * 6.022 * 10²³ = 1.5055 * 10^24.
