It’s 34 I had this question
Answer:
a. Work, ΔE is negative;
b. Work, ΔE is negative;
c. Work, ΔE is positive.
Explanation:
In the three cases, there is energy exchange in primarily work. The heat is the energy flow because of the difference in temperature. Of course, some heat may be lost in the cases by dissipation.
In the letter <em>a</em> the system is at an initial velocity different from 0, and then it stops. The energy that is represented here is the kinetic energy, which is the energy of the movement. Note that the system goes from a higher velocity to 0, so it is losing kinetic energy, or work, so ΔE = Efinal - Einitial < 0.
In letter <em>b</em>, the system is falling from a certain high to the floor, so its gravitational potential energy is change. That potential energy represents the energy that gravity does when an object shifts vertically. Because it goes from a high to 0, the energy is been lost, so ΔE = Efinal - Einitial < 0.
In letter <em>c</em>, the system is going higher and with higher velocity, so there is a greatness in the gravitational potential energy and the kinetic energy, both works, so ΔE = Efinal - Einitial > 0.
Answer:
a. Theoretical yield = 8.81 g
b. 77 %
Explanation:
We begin from the reaction:
2Fe (s) + 3Cl₂ (g) → 2FeCl₃ (s)
and the excess is the iron, so the limiting reagent is the chlorine.
We convert mass to moles → 5.78 g / 70.90 g/mol = 0.0815 mol
Ratio is 3:2 so we think this:
From 3 moles of chlorine, I can produce 2 moles of Iron (III) chloride
Then 0.0815 moles would produce (0.0815 . 2) /3 = 0.0543 moles
This is the theoretical yield. We convert the moles to mass:
0.0543 mol . 162.2 g /mol = 8.81 g
If the reaction yields 6.79 g of FeCl₃ and the theoretical yield is 8.81 g ,we can obtain the percent yield: (6.79 / 8.81) . 100 = 77 %
Answer: Star formation begins when the denser parts of the cloud core collapse under their own weight/gravity. These cores typically have masses around 104 solar masses in the form of gas and dust. The cores are denser than the outer cloud, so they collapse first.
Hope this helped! :))
The will be c. Covalent bond and
