The given dehydration equation is,

Cadmiumnitrate tetrahydrate when heated dehydrates releasing the combined water as water vapor. The reaction produces 4 moles of gaseous product water vapor. So, the degree of disorder or randomness increases. Hence, the sign of change in entropy is positive.
This reaction is spontaneous at room temperature even if it is endothermic as the sign of change in entropy is positive.
Answer:
Therefore the theoretical density of iron is 7.877 g/cm³ .
Therefore the number of vacancy per cm³ is
Explanation:
BCC structure contains 2 atoms per cell.
BCC : Body centered cubic.
Atomic mass of iron = 55.845 gram/mole.
Atomic mass of a chemical element is the mass of 1 mole of the chemical element.
Density: Density of a matter is the ratio of mass of the matter and volume of the matter.
Avogrdro Number is number of atoms per 1 mole.
Avogrdro Number= 6.023×10²³
Lattice parameter of iron = 2.866×10⁻⁸ cm
The theoretical density:

g/cm³ [x= 2,Since it is BCC structure]
=7.877 g/cm³
Therefore the theoretical density of iron is 7.877 g/cm³ .
Now we have to find out the number of unit cell of iron crystal having density 7.874 g/cm³.



⇒ x =1.9923 atom/cell
Therefore the vacancy of atom per cell = (2- 1.9923)=0.0077



Therefore the number of vacancy per cm³ is 
When a sample of a gas is heated in a sealed, rigid
container from 200 degree Kelvin to 400 degree Kelvin, the pressure exerted by
the gas is increased by a factor 2. Heating any gas actually increases the
volume of the gas within a container. As the temperature of the gas rises, the
molecules of the gas start moving faster and start striking the walls of the
container in which it is kept with more force. The volume of the container
tries to expand to accommodate the fast colliding molecules of the gas.
Answer:
1
The heat of reaction is 
The enthalpy is 
2
The concentration of HCl is 
Explanation:
From the question we are told that
The volume of
is 
The number of concentration of
is 
The volume of HCl is
The number of concentration of
is 
The temperature difference is 
Now the heat of reaction is mathematically represented as

Where
is the specific heat of water with value 

Now 
where
is the molar mass of NaOH with the value of 0.04 kg/mol
So 
While

Where
is the molar mass of
with the value of 0.03646 kg/mol


So


=> 

The enthalpy is mathematically represented as

=> 
From the second question we are told that
The volume of HCl is 
The volume of NaOH is 
The concentration of NaOH is 
The first temperature change is 
The second volume of 
The mass of NaOH is

substituting values


The mass of the product formed is

substituting values
The multiplication by 1000 is to convert it from kg to grams

Now the mass of HCl is

substituting values


Now the concentration of HCl is

The multiplication of
is to convert it from kg/mol to g/mol


Answer: Option (B) is the correct answer.
Explanation:
According to the given reaction equation, formula to calculate
is as follows.
= coefficients of gaseous products - gaseous reactants
= 1 - 0
= 1
Also we know that,



For the equation, 
Activity of solid and liquid = 1
As, 

Hence,
= 0.0056 atm
Thus, we can conclude that partial pressure of oxygen gas at equilibrium is 0.0056 atm.