<u>Answer:</u> The activation energy of the reverse reaction is 47 kJ/mol
<u>Explanation:</u>
The chemical equation for the decomposition of dinitrogen pentaoxide follows:
We are given:
Activation energy of the above reaction (forward reaction) = 102 kJ/mol
Enthalpy of the reaction = +55 kJ/mol
As, the enthalpy of the reaction is positive, the reaction is said to be endothermic in nature.
To calculate the activation energy for the reverse reaction, we use the equation:
where,
= Activation energy of the forward reaction = 102 kJ/mol
= Activation energy of the backward reaction = ?
= Enthalpy of the reaction = +55 kJ/mol
Putting values in above equation, we get:
Hence, the activation energy of the reverse reaction is 47 kJ/mol
Answer:
Option A = atomic masses
Explanation:
In compound molecular mass is the sum of the individual atomic masses of the atoms.
For example
Compound NaCl.
atomic weight of sodium = 23 g/mol
atomic weight of chlorine = 35.5 g/mol
Molar mass of NaCl = 23+ 35.5 = 58.5 g/mol
Every atom consist of nucleus or a positive center. The protons and neutrons are present with in the nucleus while electrons are present out side the nucleus. All these three subatomic particles construct an atom. The number of protons or number of electrons are the atomic number of an atom while the number of protons and number of neutrons are the mass number of an atom. A neutral atom have equal number of protons and electrons. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other.
Because there to tiny to see
The original concentration of the acid solution is 6.175 
10^-4 mol / L.
<u>Explanation:</u>
Concentration is the ratio of solute in a solution to either solvent or total solution. It is expressed in terms of mass per unit volume
HBr + NaOH -----> NaBr + H2O
There is a 1:1 equivalence with acid and base.
Moles of NaOH = 72.90 10^-3 0.25
= 0.0182 mol.
[ HBr ] = moles of base / volume of a solution
= 0.0182 / 29.47
= 6.175 10^-4 mol / L.
