Log in
Chemistry
0
answers
0
watching
100
views
13 Dec 2019

a)Find the lime and soda ash dose to soften water to less than 120mg/L as CaCo3

b) Find the lime and soda ash dose to soften the water to practical limits

Compound Concentration, mg/L as CaCO3

CO2 4.6

Ca2+ 257.9

Mg2+ 22.2

HCO3- 248.0

SO42- 32.1

Watch
0
answers
0
watching
100
views

For unlimited access to Homework Help, a Homework+ subscription is required.

discord banner image
Join us on Discord
Chemistry Study Group
Join now

Related textbook solutions

Basic Chemistry
5 Edition,
Timberlake
ISBN: 9780134138046
Principles of Chemistry Molecular Approach
4th Edition,
Tro
ISBN: 9780134112831
Chemistry: Structure and Properties
2nd Edition,
Tro
ISBN: 9780134293936
Principles of Chemistry Molecular Approach
3rd Edition, 2014
Tro
ISBN: 9780321971944
Chemistry: A Molecular Approach
3rd Edition,
Tro
ISBN: 9780321809247
Chemistry: A Molecular Approach
5th Edition,
Tro
ISBN: 9780134874371
Principles of Chemistry: A Molecular Approach
4th Edition,
Tro
ISBN: 9780134895741
Chemistry: The Central Science
14th Edition, 2017
Brown
ISBN: 9780134414232

Related questions

Please show all steps I need to understand this question. Make clear handwriting. I want it asap. Thanks

a common approach to soften water is to adjust the chemistry of the solution to cause CaCO3(s) to precipitate. As noted previously, such processes often utilize a flow scheme like that shown in the Figure below. New solids are generated in the main reaction tank, and then the solids are separated from solution in a settling tank. However, rather than discarding all of the solids, a fraction of the settled sludge is returned to the reaction tank to provide seed crystals onto which more solid can precipitate. The relevant reaction is:

A proposed water softening process will treat a flow of 5.0 m3 /s. The objective is to induce precipitation of CaCO3(s) to reduce the dissolved Ca2+ concentration from 150 to 20 mg/L. The influent contains no CaCO3(s). The settling step is expected to be very efficient, so the CaCO3(s) concentration in the treated effluent is negligible. The figure below shows some flow streams labeled and some potentially useful control volume (CV) boundaries identified. The flow rates at three points are as follows:

Q1= 5000 L /s

Q4=4910 L / s

Q7=240 L / s

Assuming that the water volumes in the various tanks, the water flow rates, and the concentrations of all the chemicals in the system are steady over time:

A)Determine flow rates of the remaining streams.

B)Determine the concentration of CaCO3(s) solids (mg/L) in the pipe between the main reactor and the settling basin (pipe 3), the pipe leading to the sludge processing facility (pipe 6), and the pipe conveying recycled solids to the main reaction vessel (pipe 7). Assume also that the precipitation reaction occurs only in the reactor, and not in the settling tank.

Gasoline is made up of hundreds of different types of hydrocarbons. From a human health perspective, the most dangerous components of gasoline are four aromatic compounds: benzene, toluene. ethylbenzene, and xylenes (commonly abbreviated BTEX). These compounds help to boost the octane level of gasoline.

a) Write a balanced electron donor half reaction for oxidation of each BTEX compound.

b) Gasoline spills often soak through the soil and come in contact with groundwater. The BTEX compound then serve as food for microorganisms. Suppose a groundwater has been contaminated with 4.9 mg/L of benzene, 5.6 mg/L of toluene, 3.5 mg/L of ethylbenzene and 0.81 mg/L of xylenes. Calculate the concentration of dissolved oxygen needed for complete oxidation of these compounds. Express your answer in mg O2/L.

c) Is the amount you calculated in part b less than or greater than the maximum concentration of DO found in water when it is in contact with air? Answer yes or no and explain.

d) When dissolbed oxygen is depleted, microorganisms are able to use other electron acceptors, including ferric iron (Fe3+). Since ferric iron is insoluble, one of the ways you can determine if iron- reducing conditions exist is by measuring ferrous iron (Fe2+), which is soluble. Calculate the concentration of ferrous iron (MW= 55.84) that would be present in groundwater assuming complete decomposition of the BTEX compounds at the concentrations listed in part b. Express your answer in mg Fe2+/L

Weekly leaderboard

Home
Homework Help 3,900,000
Chemistry 830,000
Start filling in the gaps now
Log in