Ammonia is one of the chemical constituents of industrial waste that must be removed in a treatment plant before the waste can s
afely be discharged into a river or estuary. Ammonia is normally present in waste water as aqueous ammonium hydroxide (NH4OH-). A two-part process is frequently carried out to accomplish the removal. Lime (CaO) is first added to the wastewater, leading to the reaction
CaO + H2O --> Ca2+ + 2(OH-)
The hydroxide ions produced in this reaction drive the following reaction to the right, resulting in the conversion of ammonium ions to dissolved ammonia:
NH4+ + OH- <--> NH3(g) + H2O(l)
Air is then contacted with the wastewater, stripping out the ammonia.
a. One million gallons per day of alkaline wastewater containing 0.03 mol NH3/mole ammonia-free H2O is fed to a stripping tower that operates at 68oF. Air at 68oF and 21.3 psi contacts the wastewater countercurrently as it passes through the tower. The feed ratio is 300 ft3 air/gal wastewater, and 93% of the ammonia is stripped from the wastewater. Calculate the volumetric flow rate of the gas leaving the tower and the partial pressure of ammonia in this gas.
b. Briefly explain in terms a first-year chemistry student could understand how this process works. Include the equilibrium constant for the second reaction in your explanation.
CaO + H2O --> Ca2+ + 2(OH-)
The hydroxide ions produced in this reaction drive the following reaction to the right, resulting in the conversion of ammonium ions to dissolved ammonia:
NH4+ + OH- <--> NH3(g) + H2O(l)
Air is then contacted with the wastewater, stripping out the ammonia.
a. One million gallons per day of alkaline wastewater containing 0.03 mol NH3/mole ammonia-free H2O is fed to a stripping tower that operates at 68oF. Air at 68oF and 21.3 psi contacts the wastewater countercurrently as it passes through the tower. The feed ratio is 300 ft3 air/gal wastewater, and 93% of the ammonia is stripped from the wastewater. Calculate the volumetric flow rate of the gas leaving the tower and the partial pressure of ammonia in this gas.
b. Briefly explain in terms a first-year chemistry student could understand how this process works. Include the equilibrium constant for the second reaction in your explanation.
1 answer:
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Answer:
For now the answer to this question is only for partial fraction. Find attached.
Answer:
The dude was killed around 6:30PM
Explanation:
Newton's law of cooling states:
where,
= initial temp
= temp of room
= temp after t hours
= how fast the temp is changing
= time (hours)
because the body was initlally 31ºC when the police found it
because that was the room temp
because the body temp drop to 30ºC after 1 hour
t = 1 because that's the time it took for the body temp to drop to 30ºC
we don't know k so we must solve for this
rearrange the equation to solve for k
plug in the numbers to solve for k
Now that we know the value for k, we can find the moment the murder occur. A crucial information that the question left out is the temperature of a human body when they're still alive. A living human body is about 37ºC. We can use that as out initial temperature to solve this problem because we can assume that the freshly killed body will be around 37ºC.
because the body was 37ºC right after being killed
because that was the room temp
because the body temp when the police found it
we solved this earlier
t = ??? we don't know how long it took from the time of the murder to when the police found the body
Rearrange the equation to solve for t
plug in the values
t ≈ 4.337 hours from the time the body was killed to when the police found it.
The police found the body at 11:00PM so subtract 4.337 from that.
11 - 4.33 = 6.66 ≈ 6:30PM