Answer:
A i. Internal energy ΔU = -4.3 J ii. Internal energy ΔU = -6.0 J B. The second system is lower in energy.
Explanation:
A. We know that the internal energy,ΔU = q + w where q = quantity of heat and w = work done on system.
1. In the above q = -7.9 J (the negative indicating heat loss by the system). w = 3.6 J (It is positive because work is done on the system). So, the internal energy for this system is ΔU₁ = q + w = -7.9J + 3.6J = -4.3 J
ii. From the question q = +1.5 J (the positive indicating heat into the system). w = -7.5 J (It is negative because work is done by the system). So, the internal energy for this system is ΔU₂ = q + w = +1.5J + (-7.5J) = +1.5J - 7.5J = - 6.0J
B. We know that ΔU = U₂ - U₁ where U₁ and U₂ are the initial and final internal energies of the system. Since for the systems above, the initial internal energies U₁ are the same, then we say U₁ = U. Let U₁ and U₂ now represent the final energies of both systems in A i and A ii above. So, we write ΔU₁ = U₁ - U and ΔU₂ = U₂ - U where ΔU₁ and ΔU₂ are the internal energy changes in A i and A ii respectively. Now from ΔU₁ = U₁ - U, U₁ = ΔU₁ + U and U₂ = ΔU₂ + U. Subtracting both equations U₁ - U₂ = ΔU₁ - ΔU₂
= -4.3J -(-6.0 J)= 1.7 J. Since U₁ - U₂ > 0 , U₂ < U₁ , so the second system's internal energy increase less and is lower in energy and is more stable.
Answer:
BRO WHAT THEY ANSWER TO UR BUT NOT MINE OK
Explanation: I THINK THE ASNSWER IS C BUT NOT SURE.... HOPE IT HELPS
A) because when gas is produced it changes chemical form whereas the chemical change is obvious.
<span>1) Humans have how many sets of teeth?
C) 4
2) Adults have how may permanent teeth?
B) 32
3) What type of food products make teeth stronger?
Cheese and Yogurt
4) What is the visible part of the tooth?
C) crown
5) What part of the tooth is harder than bone?
D) dentin
6) What part of the tooth is soft and contains the nerves?
A) pulp
7) What refers to the alignment of the teeth?
</span><span>
Occlusion</span><span>
8) The lower teeth protect what?
D) tongue
9) Malocclusion is the least common reason for referral to orthodontists.
False
10) Usually, malocclusion is hereditary.
True
11) Which type of malocclusion is commonly referred to as an overbite?
Class Two
12) Bacteria are living organisms than cause cavities.
True
13) What is the whitish film that grows on your teeth called?
Plaque
14) What is the best fighter of cavities?
Fluoride
Gingivitis is the inflammation of the
A) gums
16) Gingivitis is permanent.
False
17) Name 2 ways to fight gingivitis.
Proper Toothbrushing and Flossing
</span>Professional Dental Cleanings<span>
18) The cause of gum disease is
B) bacteria
19) Untreated, periodontitis will progress until your teeth loosen and fall out.
True
</span>
