Answer:
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Explanation:
Pressure in the container is P and volume is V.
Temperature of the helium gas molecules =
Molecules helium gas = x
Moles of helium has = 
PV = nRT (Ideal gas equation)
...[1]
After removal of helium gas only a fourth of the gas molecules remains and pressure in the container and volume should remain same.
Molecules of helium left after removal = 
Moles of helium has left after removal = 
...[2]
The temperature must be changed to 4 times of the initial temperature so as to keep the pressure and the volume the same.
Answer:
175 kJ
Explanation:
Activation energy can be defined as the potential energy that is needed to change reactants to products. This is the minimum energy required for the chemical reaction to take place. Thus, using the given figure:
Activation energy = activation complex - reactant energy
In the given figure, activation complex = 400 kJ
reactant energy = 225 kJ
Therefore:
Activation energy = 400 - 225 = 175 kJ
When a solid turns to gas it is called sublimation, and when a gas turns into a liquid it is called deposition
Explanation:
The given data for case (1) is as follows.
h = 20 cm = 0.2 m
Assuming that a rectangular slab is placed above the pipe and we will calculate the heat transfer as follows.
Q = 
where, A = area
L = length
k = thermal conductivity = 0.8 W/m
= change in temperature.
Therefore, putting the given values into the above formula as follows.
Q =
= 
= 168 W
For case (2), h = 180 cm = 1.8 m
Therefore, heat lost will be calculated as follows.
Q =
= 
= 18.67 W
Thus, we can conclude that 18.67 W heat lost if the pipe was buried at a depth of 180 cm.
Answer:
Iron (II) nitrate is ionic compound
Explanation:
Formula:
Fe(NO₃)₂
Iron (II) nitrate is ionic compound.
Its molecular mass is 179.85 g/mol.
NO⁻₃ is anion while Fe⁺² is cation.
Iron loses its two electron which is accepted by nitrate.
Its molecular formula can be written as FeN₂O₆.
Its color is pale green.
Its melting point is 333.65 K.
It is para magnetic compound.
it is mostly present in non hydrated form.
It is also known as ferric nitrate.
It is used to form sodium amide.
Its is also used catalyst.
