Answer:
Value of
for the given redox reaction is 
Explanation:
Redox reaction with states of species:

Reaction quotient for this redox reaction:
![Q_{p}=\frac{[Cr^{3+}]^{2}.P_{Cl_{2}}^{3}}{[H^{+}]^{14}.[Cr_{2}O_{7}^{2-}].[Cl^{-}]^{6}}](https://tex.z-dn.net/?f=Q_%7Bp%7D%3D%5Cfrac%7B%5BCr%5E%7B3%2B%7D%5D%5E%7B2%7D.P_%7BCl_%7B2%7D%7D%5E%7B3%7D%7D%7B%5BH%5E%7B%2B%7D%5D%5E%7B14%7D.%5BCr_%7B2%7DO_%7B7%7D%5E%7B2-%7D%5D.%5BCl%5E%7B-%7D%5D%5E%7B6%7D%7D)
Species inside third braket represent concentration in molarity, P represent pressure in atm and concentration of
is taken as 1 due to the fact that
is a pure liquid.
![pH=-log[H^{+}]](https://tex.z-dn.net/?f=pH%3D-log%5BH%5E%7B%2B%7D%5D)
So, ![[H^{+}]=10^{-pH}](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%3D10%5E%7B-pH%7D)
Plug in all the given values in the equation of
:

Answer:
121 million joules energy is released
Explain :
As there are 500 moles of hydrogen gas in a kilogram, this means that burning a kilogram of hydrogen gas releases 500 times as much energy or 121 million joules .
Answer:
13.5 years
Explanation:
Initial Concentration [Ao] = 10g
Final Concentration [A] = 0.768g
Time t= 50 years
Half life t1/2 = ?
These quantities are related by the following equations;
ln[A] = ln[Ao] - kt ......(i)
t1/2 = ln(2) / k ...........(ii)
where k = rate constant
Inserting the values in eqn (i) and solving for k, we have;
ln(0.768) = ln(10) - k (50)
-0.2640 = 2.3026 - 50k
50k = 2.3026 + 0.2640
k = 2.5666 / 50 = 0.051332
Insert the value of k in eqn (ii);
t1/2 = ln(2) / k
t1/2 = 0.693 / 0.051332 = 13.5 years
Answer:
50g iron comprises 5.376 × 1023 atoms.
Explanation: