Answer:
why are you trying to find a date on a homework help website?
Answer:
ΔH = -976.5 kJ
Explanation:
For the reaction given, there are 2 moles of benzene (C6H6). The heat of this reaction is -6278 kJ, which means that the combustion of 2 moles of benzene will lose 6278 kJ of heat. It is an exothermic reaction.
The value of ΔH, the enthalpy, is a way of measurement of the heat, and it depends on the quantity of the matter (number of moles).
So, 24.3 g of benzene has :
n = mass/ molar mass
n = 24.3/78.11
n = 0.311 moles
2 moles ------------ -6278 kJ
0.311 moles ----------- x
By a simple direct three rule:
2x = -1953.08
x = -976.5 kJ
Explanation:
When pH of the solution is 11.
![pH=-\log[H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D)
![11=-\log[H^+]](https://tex.z-dn.net/?f=11%3D-%5Clog%5BH%5E%2B%5D)
![[H^+]=1\times 10^{-11} M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D1%5Ctimes%2010%5E%7B-11%7D%20M)
..(1)
At pH = 11, the concentration of 
ions is 
.
When the pH of the solution is 6.
![pH=-\log[H^+]'](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BH%5E%2B%5D%27)
![6=-\log[H^+]'](https://tex.z-dn.net/?f=6%3D-%5Clog%5BH%5E%2B%5D%27)
![[H^+]'=1\times 10^{-6} M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%27%3D1%5Ctimes%2010%5E%7B-6%7D%20M)
..(2)
At pH = 6, the concentration of ions is 
.
On dividing (1) by (2).
![\frac{[H^+]}{[H^+]'}=\frac{1\times 10^{-11} M}{1\times 10^{-6}}=1\times 10^{-5}](https://tex.z-dn.net/?f=%5Cfrac%7B%5BH%5E%2B%5D%7D%7B%5BH%5E%2B%5D%27%7D%3D%5Cfrac%7B1%5Ctimes%2010%5E%7B-11%7D%20M%7D%7B1%5Ctimes%2010%5E%7B-6%7D%7D%3D1%5Ctimes%2010%5E%7B-5%7D%20)
The ratio of hydrogen ions in solution of pH equal to 11 to the solution of pH equal to 6 is 
.
Difference between the ions at both pH:
This means that Hydrogen ions in a solution at pH = 7 has 
ions fewer than in a solution at a pH = 6
Answer: A
Explanation: because of its positive and negative charges
100 mm = 100/1000= .1 meters
1cm = 1/100 = .01m
10 decimeters = 10/10 = 1 meter
.0001 km = .0001*1000 = .1 meter
