Chloroform flows through a 4.26 inch inside-diameter pipe at the rate of 3.60 gallons per minute. What is the average velocity o
1 answer:
Answer:
1) 0,081 ft/s
2) 0,746 lb/s
Explanation:
The relation between flow and velocity of a fluid is given by:
Q=Av
where:
- Q, flow [ft3/s]
- A, cross section of the pipe [ft2]
- v, velocity of the fluid [ft/s]
1)
To convert our data to appropiate units, we use the following convertion factors:
1 ft=12 inches
1 ft3=7,48 gallons
1 minute=60 seconds
So,
As the pipe has a circular section, we use A=πd^2/4:
Finally:
Q=vA......................v=Q/A
2)
The following formula is used to calculate the specific gravity of a material:
SG = ρ / ρW
where:
- SG = specific gravity,
- ρ = density of the material [lb/ft3]
- ρW = density of water [lb/ft3] = 62.4 lbs/ft3
then:
ρ = SG*ρW = 1,49* 62,4 lb/ft3 = 93 lb/ft3
To calculate the mass flow, we just use the density of the chloroform in lb/ft3 to relate mass and volume:
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<h2>Steps:</h2>
- Remember that Density = mass/volume, or D = m/v
So firstly, we have to find the volume of the rock. To do this, we need to subtract the volume of water A from the volume of the water B. In this case:
- Water A = 30 mL
- Water B = 40 mL
- 40 mL - 30 mL = 10 mL
<u>The volume of the rock is 10 mL.</u>
Now that we have the volume, we can plug that and the density of the rock into the density equation to solve for the mass.
For this, multiply both sides by 10:
<u>Rounding to the tenths place, the mass of the rock is 36.8 g, or C.</u>
Answer :
The correct answer for primary component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
<u>Buffer solution :</u>
It is a solution of mixture of weak acid and its conjugate base OR weak base and its conjugate acid . It resist any change in solution when small amount of strong acid or base is added .
<u>Capacity of a good buffer : </u>
A good buffer is identified when pH = pKa .
From Hasselbalch - Henderson equation which is as follows :
If [A⁻] = [HA] ,
pH = pka + log 1
pH = pKa
This determines that if concentration of weak acid and its conjugate base are changed in small quantity , the capacity of buffer to maintain a constant pH is greatest at pka . If the amount of [A⁻] or [HA] is changed in large amount , the log value deviates more than +/- 1M and hence pH .
Hence Buffer has best capacity at pH = pka .
<u>Phosphate Buffer : </u>
Phosphate may have three types of acid-base pairs at different pka ( shown in image ).
Since the question is asking the pH = 7.4
At pH = 7.4 , the best phosphate buffer will have pka near to 7.4 .
If image is checked the acid - base pair " H₂PO₄⁻ and HPO₄²⁻ has pka 7.2 which is near to pH = 7.4 .
Hence we can say , the primary chemical component of phosphate buffer at pH = 7.4 is H₂PO₄⁻ and HPO₄²⁻ .
