Answer:
Ka = 0.1815
Explanation:
Chromic acid
pH = ?
Concentration = 0.078 M
Ka = ?
HCl
conc. = 0.059M
pH = -log(H+)
pH = -log(0.059) = 1.23
pH of chromic acid = 1.23
Step 1 - Set up Initial, Change, Equilibrium table;
H2CrO4 ⇄ H+ + HCrO4−
Initial - 0.078M 0 0
Change : -x +x +x
Equilibrium : 0.078-x x x
Step 2- Write Ka as Ratio of Conjugate Base to Acid
The dissociation constant Ka is [H+] [HCrO4−] / [H2CrO4].
Step 3 - Plug in Values from the Table
Ka = x * x / 0.078-x
Step 4 - Note that x is Related to pH and Calculate Ka
[H+] = 10^-pH.
Since x = [H+] and you know the pH of the solution,
you can write x = 10^-1.23.
It is now possible to find a numerical value for Ka.
Ka = (10^-1.23))^2 / (0.078 - 10^-1.23) = 0.00347 / 0.0191156
Ka = 0.1815
No because it changes its composition to ozone
Answer:
Q = 306 kJ
Explanation:
Given that,
Mass, m = 60 kg
Specific heat, c = 1020 J/kg°C
The temperature changes from 20°C to 25°C.
Let Q be the change in thermal energy. The formula for the heat released is given by :
Put all the values,
So, 306 kJ is the change in thermal energy.
The reaction given is:
4Ga + P4 ---> 4GaP
The oxidation number of the reactants is zero, because they are pure elements.
The P in compounds may have oxidation states 3- or 5-. Gallium may only have oxidation state 3+.
Then, to be neutral in GaP the oxidation states are 3+ for Ga and 3- for P.
And the transference of electrons can be see in this oxidation - reduction equations:
Ga (0) - 3 e- ----> Ga (3+)
P (0) + 3e- ---> P (3-)
So, for one formula unit, 3 electrons have been transfered from each Ga atom to P atom to form one GaP unit.
Answer: 3 electrons.
