A caldera is a large cauldron-like depression that forms following the evacuation of a magma chamber or reservoir. When large volumes of magma are erupted over a short time, structural support for the crust above the magma chamber is lost, and the entire structure caves in and forms a large bowl-like shape.
Answer:
The rate of increase of the energy content of the room when all the eletrical devices are on is 1650 W.
Explanation:
From conservation of energy,
Rate of energy transfer () = Rate of change of energy within the room ().
As according to the problem no heat transfer occurs through the walls of the room we can assume that there is no energy transferred to the outside of the room, i.e., .
If all the electric devices are on inside the room, then the rate of increase of energy is equal to the power () consumed bt the electrical devices inside the room. Therefore we can write,
<u>Given:</u>
Enthalpy of dissolution for NaOH = 44 kJ/mol
Mass of NaOH = 12.6 g
Mass of water = 250 g
Initial temperature of water T1 = 23 C
<u>To determine:</u>
The final temperature of water, T2
<u>Explanation:</u>
Molar mass of NaOH = 40 g/mol
# moles of NaOH = 12.6 g/ 40 g.mol-1 = 0.315 moles
Heat released during dissolution of 0.315 moles of NaOH=
= 44 * 0.315 = 13.86 kJ = 13860 J
Heat released by NaOH = heat absorbed by water
13860 = m*c*(T2-T1)
13860 = 250*4.18*(T2-23)
T2 = 36.26 C
Ans: The final temperature of water is 36.3 C