Explanation:
The given data for case (1) is as follows.
h = 20 cm = 0.2 m
Assuming that a rectangular slab is placed above the pipe and we will calculate the heat transfer as follows.
Q = 
where, A = area
L = length
k = thermal conductivity = 0.8 W/m
= change in temperature.
Therefore, putting the given values into the above formula as follows.
Q =
= 
= 168 W
For case (2), h = 180 cm = 1.8 m
Therefore, heat lost will be calculated as follows.
Q =
= 
= 18.67 W
Thus, we can conclude that 18.67 W heat lost if the pipe was buried at a depth of 180 cm.
Explanation:
I think the answer is this for a better check mass- mass ratio in stoichiometry lesson
<span>A chemist adds 155.0ml of a 4.10 X 10^-5 mmol/L of a zinc oxalate (ZnC2O4)solution to a reaction flask. Calculate the mass in micrograms of zinc oxalate the chemist has added to the flask.
1mmol = 10^-3 mol
Therefore 4.10*10^-5mmol = 4.10*10^-8mol
molar mass ZnC2O4 = 65.39+(2*12.011)+(4*15.99) = 153.372g/mol
You have 4.10*10^-8 mol/litre =153.372 * 4.10*10^-8 = 6.29*10^-6 grams / litre (* see below)
But you have 155ml. Mass of ZnC2O4 = 155/1000*6.29*10^-6 g
Mass is = 9.75*10^-7 grams
1µg = 10^-6 g
You then have 9.75*10^-7/10^-6 = 0.975µg ZnC2O4
(*see below) at this point you could have said:
1µg = 10^-6 g therefore you have a solution of 6.29µg per litre,
155ml = 6.29*155/1000 = 0.975µg ZnC2O4</span>
Na⁺,SO₄²⁻ is the answer
<h3>Further explanation
</h3>
An ion is an atom or molecule that has a net electrical charge. There are many ions, one of them are sodium ion and sulfate ion.
SO₄²⁻ or Sulfate is a naturally occurring polyatomic ion that consist of a central sulfur atom surrounded by four oxygen atoms with occured widely in everyday life. Sodium ions are important for regulation of blood and body fluids, transmission of nerve impulses, heart activity, and certain metabolic functions.
Whereas Na⁺ or Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sulfate ion is a very weak base. Therefore sulfate ion undergoes negligible hydrolysis in aqueous solution.
Enter the symbol of a sodium ion, Na⁺, followed by the formula of a sulfate ion, SO₄²⁻. Separate the ions with a comma only—spaces are not allowed. Express your answers as ions separated by a comma. Therefore the answer is: Na⁺,SO₄²⁻
Hope it helps!
<h3>Learn more</h3>
- Learn more about sodium ion brainly.com/question/6839866
- Learn more about sulfate ion brainly.com/question/2763823
- Learn more about ions brainly.com/question/11852357
<h3>Answer details</h3>
Grade: 9
Subject: Chemistry
Chapter: Introduction to Mastering Chemistry
Keywords: sodium ion, sulfate ion, ions, Chemistry, symbol
Answer:
Explanation:
Hello there!
In this case, since the vaporization process is carried out in order to turn a liquid into a gas due to the addition of heat, we can use the following heat equation involving the heat of vaporization of water or any other substance:
Thus, since this heat of vaporization for water is 2259.36 J/g, we plug in this amount to obtain the total energy for this process.
Which is positive due to the necessity of heat.
Regards!
