1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
torisob [31]
2 years ago
10

The raw water supply for a community contains 18 mg/L total particulate matter. It is to be treated by addition of 60 mg alum (A

l2(SO4)3 14H2O) per liter of water treated. Essentially, all the added alum precipitates represented by the following reaction:
Required:
a. For a total flow of 8000 m^3/d, compute the daily alum requirement and the concentration of solids in the water following alum addition, assuming the alum all precipitates as Al(OH)3(s).
b. The water is initially at pH 7.5 and has ALK=40 mg/L as CaCO3. It is desired to maintain solution pH at 6.5 or higher. Will the pH be in the acceptable range after the chemical addition and Al(OH)3(s) precipitation?
c. What will the pH be if the treated solution is bubbled with air, so that it reached equilibrium with atmospheric CO2?
Chemistry
1 answer:
s344n2d4d5 [400]2 years ago
6 0

Solution :

Given :

The steady state flow = 8000 $ m^3 /d $

                                    $= 80 \times 10^5 \ I/d $

The concentration of the particulate matter = 18 mg/L

Therefore, the total quantity of a particulate matter in fluid $= 80 \times 10^5 \ I/d \times 18 \ mg/L $

$= 144 \times 10^6 \ mg/g$

$= 144 \ kg/d $

If 60 mg of alum $ [Al_2(SO_4)_3.14 H_2O] $ required for one litre of the water treatment.

So Alum required for  $ 80 \times 10^5 \ I/d $

$= 80 \times 15^5 \ I/d  \times 60 \ mg \ alum /L$

$= 480 \times 10^6 \ mg/d $

or 480 kg/d

Therefore the alum required is 480 kg/d

1 mg of the alum gives 0.234 mg alum precipitation, so 60 mg of alum will give $ = 60 \times 0.234 \text{ of alum ppt. per litre} $

      $= 14.04 $ mg of alum ppt. per litre

480 kg of alum will give = 480 x 0.234 kg/d

                                        = 112.32 kg/d ppt of alum

Daily total solid load is  $= 144 \ kg/d + 112.32 \ kg/d$

                                       = 256.32 kg/d

So, the total concentration of the suspended solid after alum addition $= 18 \ mg/L + 60 \times 0.234 $

= 32.04 mg/L

Therefore total alum requirement = 480 kg/d

b). Initial pH = 7.4

 The dissociation reaction of aluminium hydroxide as follows :

$Al(OH)_3 \rightleftharpoons Al^{3+} + 3OH^{-} $

After addition, the aluminium hydroxide pH of water will increase due to increase in $ OH^- $ ions.

Therefore, the pH of water will be acceptable range after the addition of aluminium hydroxide.

c). The reaction of $CO_2$ and water as follows :

$CO_2 (g) + H_2O (l) \rightarrow H_2CO_3$

For the atmospheric pressure :

$p_{CO_2} = 3.5 \times 10^{-4} \ atm $

And the pH is reduced into the range of 5.9 to 6.4

You might be interested in
If a solution containing 51.429 g of mercury(ii) perchlorate is allowed to react completely with a solution containing 16.642 g
OLga [1]
Hg(No3)2  +NaSO4   --->2NaNO3  +  HgSO4(s)
calculate  the moles  of   each  reactant
moles=mass/molar  mass

moles of  Hg(NO3)2=  51.429g/  324.6  g/mol(molar  mass  of  Hg(NO3)2)=0.158  moles

moles Na2SO4  16.642g/142g/mol=  0.117  moles  of  Na2SO4

Na2SO4  is  the  limiting  reagent in  the   equation   and  by  use  mole  ratio  Na2So4  to  HgSO4  is  1:1   therefore  the  moles  of  HgSO4  =0.117  moles

mass  of  HgSO4=moles  x  molar   mass  of  HgSo4=  0.117 g x  303.6g/mol=  35.5212  grams

7 0
3 years ago
Use the picture to answer the following questions.
vesna_86 [32]
1. the producer is the wheat/plant (producers create their own energy, example is photosynthesis in plants)
2. the consumer is the bird (hint all consumers have mouths. they have to eat/ drink something to produce energy)
8 0
3 years ago
Why are fibers birefringent
horrorfan [7]

Inevitable manufacturing imperfections in optical fiber leads to birefringence, which is one cause of pulse broadening in fiber-optic communications. Such imperfections can be geometrical (lack of circular symmetry), due to stress applied to the optical fiber and/or due to bending of the fiber.

4 0
3 years ago
Read 2 more answers
How many liters of 0.85 M HCl solution would react completely with 3.5 moles Ca(OH)2?
Neporo4naja [7]
I think B but i'm not for sure
4 0
3 years ago
What is the number of atoms in 3.75 mol fe
Kruka [31]
1mol=6.022x10^23 atoms
3.75mol= 6.022x3.75x10^23 atoms
             =2.2583x10^24 atoms
8 0
3 years ago
Other questions:
  • Which of the following distinguishes a nuclear reaction from a chemical reaction? a.It involves atoms.
    12·1 answer
  • Avogadro's number refers to ___. the maximum number of electrons that all of an atom's energy levels can accommodate the number
    14·2 answers
  • Ions containing oxygen are colourless, is this true?
    6·1 answer
  • a bullet leaves the muzzle of a rifle and 5 seconds later becomes embedded in a tree trunk 3000 meters away what is the average
    12·1 answer
  • Which SI unit would be used to measure the distance from one corner of the lab table to the opposite corner
    9·1 answer
  • If 6.5 L of water is added to 4.5 L of a 2.8 M Ca(OH)2 solution, what is the molarity of the new solution?
    14·1 answer
  • Mutations in genes encoding cell signaling proteins contribute to many cancers. For example, a chromosomal translocation fuses t
    9·1 answer
  • Consider an acidic chromate-dichromate system at equilibrium in which the color is an orange-yellow. The reaction is represented
    8·1 answer
  • If the half-life of 37Rb is 4.7x101 years, how long would it take for 0.5 grams of a 2 gram sample to radioactively decay?
    13·1 answer
  • The heat of a reaction may be found with the equation q=mc triangle T. A 951 g sample of carbon steel with a specific heat capac
    6·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!