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:
p orbital.
Explanation:
Valence electrons are the electrons in an atom holding the very last orbital which is used in chemical bonding with other elements. Their existence could define the chemical properties of that atom.
During the first energy in ionization of an N2 molecule the molecular orbital from which the electron could be extracted is the only one with the highest energy level. Nitrogen has its outermost orbital (p) containing three valence electrons. Each orbital is only half filled, and thus it is unstable Thus, the electron mission must have been removed from p orbital.
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Answer:
2.1 kg of water
Explanation:
Step 1: Given data
- Moles of lithium bromide (solute): 4.3 moles
- Molality of the solution (m): 2.05 m (2.05 mol/kg)
- Mass of water (solvent): ?
Step 2: Calculate the mass of water required
Molality is equal to the moles of solute divided by the kilograms of solvent.
m = moles of solute/kilograms of solvent
kilograms of solvent = moles of solute/m
kilograms of solvent = 4.3 mol /(2.05 mol/kg) = 2.1 kg
