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junior college 1 | Chemistry
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Chowder
Chowder

junior college 1 chevron_right Chemistry

Liu Rijing help pls

Date Posted: 6 years ago
Views: 743

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Liu Rijing
Liu Rijing's answer
49 answers (A Helpful Person)
1st
0.187 days in service before replacement
Chowder
Chowder
6 years ago
But my teacher say the answer is 0.73days
Liu Rijing
Liu Rijing
6 years ago
OK please use your answer in part a to calculate the amount of CA 2+ in the water multiplies by flow rate 150 m^3
Chowder
Chowder
6 years ago
My teacher said capacity is 70kg/m3 x flowrate

Total hardness is 3125mg/L needs to be removed . But i cant get the ans . Pls help
Liu Rijing
Liu Rijing
6 years ago
Hi my answer for total hardness in terms of calcium ions is 2050 mg/L.

Taking it multiply by the flow rate 150 m^3 per day gives 307.5 kg calcium ions flow rate per day. The capacity of the resin is 22.4 kg

Taking 22.4 kg divided by 307.5 kg /day = 0.0728 days
Chowder
Chowder
6 years ago
How did u get 22.4 ? But both calcium and magnesium contributes to hardness so must plus them both right . My teacher say ans is 0.73days . Help pls
Chowder
Chowder
6 years ago
https://www.google.com.sg/amp/www.water-chemistry.in/2009/01/calculating-calcium-hardness-as-caco3/amp/ i was taught to calc it like this for mg/L as caco3
Liu Rijing
Liu Rijing
6 years ago
I get 22.4 kg by multiplying 0.8 m^3 and 70 kg CaCO3 and converting to calcium weight by dividing by MW of CaCO3 then times MW of Calcium.

I may have make a mistake in the order of my number by factor of 10 in my flow rate and capacity of resin calculation. Can you recheck my values?
Liu Rijing
Liu Rijing
6 years ago
I rechecked my calculation again, answer is 0.073 days, could your teacher make a mistake?
Liu Rijing
Liu Rijing
6 years ago
Yes both calcium and magnesium contribute to the hardness
Chowder
Chowder
6 years ago
SAME i got 0.073 . But my tcr said its 0.73 how liao leh
Liu Rijing
Liu Rijing
6 years ago
What about your classmates?
Liu Rijing
Liu Rijing
6 years ago
What is your answer for part a)
Chowder
Chowder
6 years ago
They havent do liao leh . You take environmental techno before ? Cos if not i can ask you abt these Q again :D
Liu Rijing
Liu Rijing
6 years ago
I studied chemical engineering in Nus, I think I should be able to help you on it
Chowder
Chowder
6 years ago
OMG YES I TAKE CHEM ENG TOO OMG CAN YOU HELP ME FOREVER . LIKE 2 MORE YEARS HELP ME PLS
Liu Rijing
Liu Rijing
6 years ago
Ok, you studied where? Degree or diploma?
Chowder
Chowder
6 years ago
Cn help me with another Q ? I posted a new Q cos idk how find return sludge . Help pls . You can click on my name and click the question .
Liu Rijing
Liu Rijing
6 years ago
Ok
Liu Rijing
Liu Rijing
6 years ago
Sorry I will need sometimes to answer it as I have not taken waste water treatment technology module as it is an optional elective.
Chowder
Chowder
6 years ago
But its under enrivonmental techno . I havent take any elective cluster yet . This is the core sub . But pls help me solve :(
Liu Rijing
Liu Rijing
6 years ago
Sorry chowder, I forgot about helping you, were you able to solve the sludge treatment problem
Chowder
Chowder
6 years ago
No i didnt. Please help me liao leh . We same course can help me leh
Chowder
Chowder
6 years ago
Yoh . Are u still able to help :)
Liu Rijing
Liu Rijing
6 years ago
Hi sorry, I dun know the topic well even though majored in them eng, the core content do not cover waste treatment.

I am working adult, so I also do not have the time to read up on the topic.

I try to help you on other topics in the future.
Chowder
Chowder
6 years ago
Cn help me with engineering maths 2 ? Pls? U click my name got the Q
Chowder
Chowder
6 years ago
Hi do u take occupational safety and health before
Liu Rijing
Liu Rijing
6 years ago
Yes, I took safety health and environment mod.
Chowder
Chowder
6 years ago
Can help with me maths plss
Liu Rijing
Liu Rijing
6 years ago
I am quite tired from work, what type of maths question you need help for, the 2nd order differential equations? I try to see if I have the energy to help you.
Chowder
Chowder
6 years ago
Ok:( sorry
Liu Rijing
Liu Rijing
6 years ago
You can post it, I try to answer if I can still remember how to do it
Chowder
Chowder
6 years ago
I post already
Liu Rijing
Liu Rijing
6 years ago
The particular soln linear 2nd order differential eqn?
Chowder
Chowder
6 years ago
Yes
Liu Rijing
Liu Rijing
6 years ago
OK, please give me sometimes to answer, will send by tonight.