The Law of Conservation of Energy states that, within a closed system, the total amount of energy remains constant. However, energy may change from kinetic to potential and vice versa. The total energy will not have changed. <span>Enthalpy is a measure of the amount of energy that exists in a system at constant pressure. </span>
Conduction: In the conduction, the heat is transferred from the hotter body to the colder body until the temperature on both bodies are equal.
In thermal equilibrium, there is no heat transfer as the heat is transferred till the temperature on the bodies are not same.
In the given problem, an iron bar at 200°C is placed in thermal contact with an identical iron bar at 120°C in an isolated system. After 30 minutes, the thermal equilibrium is attained. Then, the temperature on both iron bars are equal.Both iron bars are at 160°C in an isolated system.
But in an open system, the temperatures of the iron bars after 30 minutes would be less than 160°C. There will be heat lost to the surrounding. The room temperature is 25°C. There will be exchange of the heat occur between the iron bars and the surrounding. But It would take more than 30 minutes for both iron bars to reach 160°C because heat would be transferred less efficiently.
Answer:
a) 32.09 kPa
b) 32.09 kPa
Explanation:
Given data:
rate constant 
initial pressure is = 32.1 kPa
half life of A is calculated as



for calculating pressure we have follwing expression


a) 
b) 