Answers and Explanation:
a)- The chemical equation for the corresponden equilibrium of Ka1 is:
2. HNO2(aq)⇌H+(aq)+NO−2
Because Ka1 correspond to a dissociation equilibrium. Nitrous acid (HNO₂) losses a proton (H⁺) and gives the monovalent anion NO₂⁻.
b)- The relation between Ka and the free energy change (ΔG) is given by the following equation:
ΔG= ΔGº + RT ln Q
Where T is the temperature (T= 25ºc= 298 K) and R is the gases constant (8.314 J/K.mol)
At the equilibrium: ΔG=0 and Q= Ka. So, we can calculate ΔGº by introducing the value of Ka:
⇒ 0 = ΔGº + RT ln Ka
ΔGº= - RT ln Ka
ΔGº= -8.314 J/K.mol x 298 K x ln (4.5 10⁻⁴)
ΔGº= 19092.8 J/mol
c)- According to the previous demonstation, at equilibrium ΔG= 0.
d)- In a non-equilibrium condition, we have Q which is calculated with the concentrations of products and reactions in a non equilibrium state:
ΔG= ΔGº + RT ln Q
Q= ((H⁺) (NO₂⁻))/(HNO₂)
Q= ( (5.9 10⁻² M) x (6.7 10⁻⁴ M) ) / (0.21 M)
Q= 1.88 10⁻⁴
We know that ΔGº= 19092.8 J/mol, so:
ΔG= ΔGº + RT ln Q
ΔG= 19092.8 J/mol + (8.314 J/K.mol x 298 K x ln (1.88 10⁻⁴)
ΔG= -2162.4 J/mol
Notice that ΔG<0, so the process is spontaneous in that direction.
Answer: C. The number of atoms of each element is the same on each side of the equation.
Explanation:
The Law of Conservation of Matter shows that it is not possible for matter to either be created nor for it to be destroyed so the number of atoms of each element on the reactant side of the equation must equal the number of atoms in each element on the product side of the equation.
This is why the following equation is incomplete:
H₂ + O₂ ⇒ H₂O
The oxygen atoms are not the same on either side.
Equation will therefor have to be balanced which will make it:
2H₂ + O₂ ⇒ 2H₂O
Notice now that atoms are the same on both sides.
Explanation:
The given chemical equation is:
The rate of the reaction is 0.0352 M/s.
During the course of the reaction, the rate of reactants decreases, and the rate of products increases.
The rate of disappearance of B is shown below:
![rate=-\frac{1}{4} \frac{d[B]}{dt}](https://tex.z-dn.net/?f=rate%3D-%5Cfrac%7B1%7D%7B4%7D%20%5Cfrac%7Bd%5BB%5D%7D%7Bdt%7D)
So, rate of change of B is :
Option C.
