First, we convert the depth of the water into meters. This is:
60 feet = 18.3 meters
Now, we compute the additional pressure exerted due to the water, which is given by:
Pressure = density * gravitational field strength * height
P = 1000 * 9.81 * 18.3
P = 179.5 kPa
The atmosphere pressure is 101.325 kPa
The pressure of the gas bubbles 60 feet under water will be:
179.5 + 101.325 = 280.825 kPa
The pressure at the surface of the water will be equal to the atmospheric pressure, 101.325 kPa.
Because of this decrease in external pressure as gas bubbles rise, they are seen to expand.
Half reaction 1: 2Fe° → Fe₂³⁺ + 6e⁻ /×2.
4Fe° → 2Fe₂³⁺ + 12e⁻.
Iron is oxidized from neutral charge (0) to oxidation number +3, one iron lose three electrons, two irons lose six electrons and four irons twelve electrons.
Half reaction 2: 12e⁻ + 3O₂ → 2O₃²⁻
Oxygen is reduced from neutral chage to oxidation number -2, one oxygen gain two electrons, six oxygens gain twelve electrons.
Balanced chemical reaction: 4Fe + 3O₂ → 2Fe₂O₃.
Answer: The mass of ice you would need to add to bring the equilibrium temperature of the system to 300 K is
kg.
Explanation:
We know that relation between heat energy and specific heat is as follows.
q = 
As density of water is 1 kg/L and volume is given as 400,000 L. Therefore, mass of water is as follows.
Mass of water = Volume × Density
= 
= 400,000 kg
or, =
g (as 1 kg = 1000 g)
Specific heat of water is 4.2 J/gm K. Therefore, change in temperature is as follows.
= 305 K - 273 K
= 32 K
Now, putting the given values into the above formula and calculate the heat energy as follows.
q =
= 
=
J
or, =
kJ
According to the enthalpy of melting of ice 333 kJ/Kg of energy absorbed by by 1 kg of ice. Hence, mass required to absorb energy of
kJ is calculated as follows.
Mass = 
=
kg
Thus, we can conclude that the mass of ice you would need to add to bring the equilibrium temperature of the system to 300 K is
kg.
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