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:
1.634 molL-1
Explanation:
The mol ration between NH3 and HCl is 1 : 1
Using Ca Va / Cb Vb = Na / Nb where a = acid and b = base
Na = 1
Nb = 1
Ca = 0.208 molL-1
Cb = ?
Va = 19.64 mL
Vb = 25.00mL
Solving for Cb
Cb = Ca Va / Vb
Cb = 0.208 * 19.64 / 25.0
Cb = 0.1634 molL-1 (Concentration of diluted ammonia solution)
Using the dilution equation;
C1V1 = C2V2
Initial Concentration, C1 = ?
Initial Volume, V1 = 25.00 mL
Final Volume, V2 = 250 mL
Final Concentration, C2 = 0.1634 molL-1
Solving for C1;
C1 = C2 * V2 / V1
C1 = 0.1634 * 250 / 25.00
C1 = 1.634 molL-1
Among the elements Barium has the lowest Ionization Energy.
<h3>What is Ionization Process ?</h3>
The process by which any neutral atom gets converted into electrically charged by gaining or losing electron is called Ionization Process.
K is an alkali metal it has to lose one electron to attain stable electronic configuration of an inert gas
For removing second electron , a stable configuration has to be broken and so will require high amount of energy.
Ca and Ba are alkaline earth metals.
They both have to lose 2 electrons to attain stable electronic configuration of noble gas.
They have low Iow Ionization Energy as compared to K.
Ca has higher Ionization Energy as compared to Ba because when we move down the periodic table , The ionization energy decreases.
Hence , Among the elements Barium has the lowest Ionization Energy.
To know more about Ionization Process
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