The calculated pH of the solutions are given below:
- The pH of the solution after 14.0 ml of base is added to it is calculated as 1.45.
- The pH of the solution after 19.8 ml of base is added to it is calculated as 3.0
- The pH of the solution after 20.0 ml of base is added to it is calculated as 7.
<h3>What is pH?</h3>
This is the level of acidity or alkalinity of an aqueous solution. The pH of a substances tells if its an acid, base or neutral.
HBr and NaOH while in water would dissociate and they would become H+ and OH- respectively.
Mol of HBr = Mol * Vol
= 0.200 * 20mL
= 4 mmol
A. Moles of NaOH added
= 0.2 X 14
= 2.8 mmol
Moles of H+ that did not react
= 4 - 2.8
= 1.2 mmol
1.2/1000 = 0.0012 moles
Total volume = 20 + 14
= 34 mL to litres
= 0.034 L
Molarity of H+ = 0.0012 / 0.034L
= 0.035 M
-log[0.035] = 1.45
The pH of the solution is 1.45
B. NaOH added = 19.8 * 0.2 =
3.96 mmoles
The unreacted solution
= 4.0 - 3.96
= 0.04 mmol
0.04/1000 = 0.00004 moles
Total volume = 20 + 19.8
= 39.8mL
Converted to litres = 0.0398L
Molarity = 0.00004 / 0.0398L
= 0.001
-log(0.001) = 3.0
The ph Is therefore 3.0
C. Moles of NaOH added = 0.2*20mL = 4mmol
All the H+ are going to be consumed here. This would result into a neutral solution pH = 7
<u>Complete question:</u>
20.0 mL sample of 0.200 M HBr solution is titrated with 0.200 M NaOH solution. Calculate the PH of the solution after the following volumes of base have been added.
A. 14.0 mL
B. 19.8 mL
C. 20.0 mL
Read more on pH here; brainly.com/question/22390063
The true statement about the directrix is that each directrix of this ellipse is 31.25 units from the center on the major axis.
<h3>How to determine the distance of the directrix?</h3>
The equation of the ellipse is given as:
The above means that:
a^2 = 625
a = 25
b^2 = 225
b = 15
Calculate c using:
c^2 = a^2 - b^2
This gives
c^2 = 625 - 225
Evaluate the difference
c^2 = 400
Evaluate the square root
c = 20
The equation of the directrix is
x - x₀ = ± a²/c
So, we have:
x - x₀ = ± 625/20
Evaluate the quotient
x - x₀ = ± 31.25
This means that, each directrix is 31.25 units from the center on the major axis.
Read more about directrix at:
brainly.com/question/26109874
Answer:
- National Government: Every nation needs an authorised administration, which would serve the people of the nation. The role of the National Government is to ensure protection, to give proper education, to protect civil rights and to offer all the necessary commodities (including foods, clothes, materials, etc.) nationwide. National Government works on foreign policies to bring various economical or scientific services to its people.
• Provincial Government: A Provincial Government has administrative power over a province within the nation, under the structural institution of National Government. It works to serve the civil society with education, health and social development. It also takes care of agriculture and roads. Moreover Provincial Government connects National Government with Local Government constitutionally
- Local Government: A local government is the lowest part of governance. It is a form of public administration locally. The power to local government is delegated to them by provincial legislature.
answer
1). Airplane is flying at 14551 feet.
2). Height of the mountain is 4299 feet.
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1). An airplane starts at the level = 0 feet
It rose to the altitude = 21000 feet
It descends by the height due to clouds = 4329 feet
So the height of the airplane = 21000 - 4329
= 16671 feet
After giving pass to a plane it ascends by the height = 6333 feet
Now the height of the airplane = 16671 + 6333
= 23004 feet
Then the airplane descends again to give the pass to a airplane again.
Altitude after descending by 8453 feet = 23004 - 8453 = 14551 feet
Airplane is flying at 14551 feet.
2). Distance between the top of the mountain to the floor of the valley = 4392 feet
Valley is 93 feet below the sea level.
Therefore, the height of the mountain will be = 4392 - 93
= 4299 feet
hope this helps you
