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Allushta [10]
3 years ago
12

Plateau Creek carries 5.0 m^3 /s of water with a selenium (Se) concentration of 0.0015 mg/L. A farmer withdraws water at a certa

in flowrate (m3 /s) from the creek for irrigation. After using the water, half of the water withdrawn returns to the creek and contains 1.00 mg/L of Se. Fish in the creek are sensitive to Se levels over 0.04 mg/L.
Required:

How much water (m3 /s) can the farmer withdraw from the stream to maintain Se at 0.04 mg/L after the contaminated water is returned to the creek?
Engineering
1 answer:
Bond [772]3 years ago
7 0

Answer:

The correct answer is "4.8137 m³". The further explanation is given below.

Explanation:

Firstly we have to calculate the concentration of Se:

C = 0.0015 \ mg/L\times \frac{1g}{1000 mg}\times \frac{1 \ mol}{79 \ g}

   =1.9\times 10^{-8} \ mol/L

Concentration the fish can take:

=0.04 \ mg/L\times \frac{1 \ g}{1000mg}\times \frac{1 \ mol}{79 \ g}

According to the general dilution principle will be:

⇒  M_1V_1 = M_2V_2

The volume that can take the farmer will be:

V_2 = 1.9\times 10^{-8} M\times  \frac{5\times 10^3 \ L}{5.1\times 10-7 M}

    =186.27 \ L

On converting this into m³, we get

= 0.18627 \ m^3

Finally the volume the farmer can remove would be:

V = 5-0.18627

   = 4.8137 \ m^3

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The ___________ section of the bid package might include information concerning provisions for water and other utilities, sanita
dexar [7]

Answer:

Procurement Process

Explanation:

Procurement Process describes the series of activities that an organization partakes in to get products or services in order to achieve their goals. The choice of the procurement process is very important for the success of a construction project.

So during a bidding process, the procurement process is section where the organization will need to get water and other utilities, sanitation equipment or storage needed for the success of a construction project.

3 0
3 years ago
Which of the following is true about ideal standards? a.Ideal standards provide allowance for normal breakdowns and interruption
marysya [2.9K]

Answer: D. All of the choice A, B and C are correct.

8 0
3 years ago
Calculate the theoretical density of FCC iron (eg. austenitic stainless steel). The lattice parameter for FCC iron is 0.357 nm a
Ann [662]

Answer: 12.4 feet

Explanation:

If there is a smooth transition and there is no change in slopes, energy considerations can be used

The cube has a kinetic energy of

ke = mv^2/2 = 10 lbm * 20^2ft^2/s^2 / 2 = 2000 lbm-ft^2 / s^2

At the highest point when there is a gain in potential energy

pe = mgh = 10 lbm * 32.2 ft/s^2 * h ft = 322 lbm ft^2/s^2

If there is no loss in energies,

pe = ke

322h lbm ft^2/s^2 = 2000 lbm ft^2/s^2

h = 2000 /322 = 6.211 (ft)

= h / sin(30) = 12.4 ft

8 0
3 years ago
The time to half-maximum voltage is how long it takes the capacitor to charge halfway. Based on your experimental results, how l
satela [25.4K]

Answer:

Time taken for the capacitor to charge to 0.75 of its maximum capacity = 2 × (Time take for the capacitor to charge to half of its capacity)

Explanation:

The charging of a capacitor/the build up of its voltage follows an exponential progression and is given by

V(t) = V₀ [1 - e⁻ᵏᵗ]

where k = (1/time constant)

when V(t) = V₀/2

(1/2) = 1 - e⁻ᵏᵗ

e⁻ᵏᵗ = 0.5

In e⁻ᵏᵗ = In 0.5 = - 0.693

-kt = - 0.693

kt = 0.693

t = (0.693/k)

Recall that k = (1/time constant)

Time to charge to half of max voltage = T(1/2)

T(1/2) = 0.693 (Time constant)

when V(t) = 0.75

0.75 = 1 - e⁻ᵏᵗ

e⁻ᵏᵗ = 0.25

In e⁻ᵏᵗ = In 0.25 = -1.386

-kt = - 1.386

kt = 1.386

t = 1.386(time constant) = 2 × 0.693(time constant)

Recall, T(1/2) = 0.693 (Time constant)

t = 2 × T(1/2)

Hope this Helps!!!

3 0
3 years ago
Read 2 more answers
Imagine the reaction A + B LaTeX: \Longleftrightarrow⟺ C + D proceeds at room temperature (25 °C) and is determined to have a re
Wittaler [7]

Answer:

0.2 kcal/mol is the value of \Delta G for this reaction.

Explanation:

The formula used for is:

\Delta G_{rxn}=\Delta G^o+RT\ln Q

\Delta G^o=-RT\ln K

where,

\Delta G_{rxn} = Gibbs free energy for the reaction

\Delta G_^o =  standard Gibbs free energy  

R =Universal  gas constant

T = temperature

Q = reaction quotient

k = Equilibrium constant

We have :

Reaction quotient of the reaction = Q = 46

Equilibrium constant of reaction = K = 35

Temperature of reaction = T = 25°C = 25 + 273 K = 298 K

R = 1.987 cal/K mol

\Delta G_{rxn}=-RT\ln K+RT\ln Q

=-1.987 cal/K mol\times 298 K\ln [35]+1.987 cal/K mol\times 298K\times \ln [46]

=-2,105.21 cal/mol+2,267.04 cal/mol=161.82 cal/mol=0.16182 kcal/mol\approx 0.2 kcal/mol

1 cal = 0.001 kcal

0.2 kcal/mol is the value of \Delta G for this reaction.

5 0
3 years ago
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