We write DE = q+w, where DE is the internal energy change and q and w are heat and work, respectively.
(b)Under what conditions will the quantities q and w be negative numbers?
q is negative when heat flows from the system to the surroundings, and w is negative when the system does work on the surroundings.
As an aside: In applying the first law, do we need to measure the internal energy of a system? Explain.
The absolute internal energy of a system cannot be measured, at least in any practical sense. The internal energy encompasses the kinetic energy of all moving particles in the system, including subatomic particles, as well as the electrostatic potential energies between all these particles. We can measure the change in internal energy (DE) as the result of a chemical or physical change, but we cannot determine the absolute internal energy of either the initial or the final state. The first law allows us to calculate the change in internal energy during a transformation by calculating the heat and work exchanged between the system and its surroundings.
<h2><u>Answer</u> : - </h2>
Polywool fibre is <u>synthetic</u>.
⇒b. Synthetic
Hope It Helps You ✌️
The Law of Conservation of Matter states that matter cannot be created or destroyed. In a physical change, substances can change form, but the total mass remains the same.
The only true statement about an exterior angle of a triangle from the above is that it forms a linear pair with one of the interior angles of the triangle.
<h3>What is a triangle?</h3>
A triangle can be defined as a one of the plane shapes which has three sides and three angles
So therefore, the only true statement about an exterior angle of a triangle from the above is that it forms a linear pair with one of the interior angles of the triangle.
Learn more about triangles:
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<h3>Explanation</h3>
Units of each quantity:
- <em>P</em> = 28 atm;
- <em>V</em> = 0.045 L;
- <em>n</em> = 0.020 mol;
Ideal gas constant:
.
Apply the ideal gas law:
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All data given in this question come with two significant figures. Round the value of <em>T</em> to two significant figures:
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