<u>Answer:</u> The molarity of KOH is 0.84 M.
<u>Explanation:</u>
To calculate the concentration of base, we use the equation given by neutralization reaction:

where,
are the n-factor, molarity and volume of acid which is 
are the n-factor, molarity and volume of base which is KOH.
We are given

Putting values in above equation, we get:

Hence, the molarity of KOH is 0.84 M.
Use Arrhenius equation:
k = A*exp(-Ea/RT)
We have:
1.35x10^2/s = A*exp(-85600/(8.314*298.15))
or: A = 1.342x10^17/s
It is a piece of cake to calculate:
k = 1.342x10^17*exp(-85600/(8.314*348.15))
= 1.92x10^4/s
Answer:
1.71 kJ/mol
Explanation:
The expression for the calculation of the enthalpy change of a process is shown below as:-
Where,
is the enthalpy change
m is the mass
C is the specific heat capacity
is the temperature change
Thus, given that:-
Mass of CaO = 1.045 g
Specific heat = 4.18 J/g°C
So,
Also, 1 J = 0.001 kJ
So,

Also, Molar mass of CaO = 56.0774 g/mol

Thus, Enthalpy change in kJ/mol is:-

Answer: There are 0.5 grams of barium sulfate are present in 250 of 2.0 M
solution.
Explanation:
Given: Molarity of solution = 2.0 M
Volume of solution = 250 mL
Convert mL int L as follows.

Molarity is the number of moles of solute present in liter of solution. Hence, molarity of the given
solution is as follows.

Thus, we can conclude that there are 0.5 grams of barium sulfate are present in 250 of 2.0 M
solution.
Slow chemical change
It is a chemical change because the erosion is due to the chemical reaction between the acid and the in the rain and the calcium carbonate.
It is slow due to the concentration of acid is low.