Answer:
25kJ
Explanation:
Given the initial energy to be 30kJ
The energy change from the initial energy to the peak energy = (65-30) kJ
= 35kJ
since the second energy change was a drop in energy it is regarded negative
= (55-65)
= -10kJ
Therefore total energy change
= (35-10)kJ
= 25kJ
Answer: The correct option is (c). The total pressure doubles.
Solution:
Initially, only 4 moles of oxygen gas were present in the flask.
(
) ( according to Dalton's law of partial pressure)
....(1)
= Total pressure when only oxygen gas was present.
Final total pressure when 4 moles of helium gas were added:

partial pressure of oxygen in the mixture :
Since, the number of moles of oxygen remains the same, the partial pressure of oxygen will also remain the same in the mixture.

= Total pressure of the mixture.
from (1)

On rearranging, we get:

The new total pressure will be twice of initial total pressure.
Answer:
Salt water is, A. a mixture
Answer: The osmotic pressure of a solution is 53.05 atm
Explanation:
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

Or,

where,
= osmotic pressure of the solution = ?
i = Van't hoff factor = 1 (for non-electrolytes)
Mass of solute (methanol) = 22.3 g
Volume of solution = 321 mL
R = Gas constant = 
T = temperature of the solution = ![25^oC=[273+25]=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B273%2B25%5D%3D298K)
Putting values in above equation, we get:


Hence, the osmotic pressure of a solution is 53.05 atm