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.
Explanation:
The given data is as follows.
Pressure (P) = 170 torr, mass of heptane (m) = 86.7 g
First, we will calculate the number of moles as follows.
No. of moles = 
= 
= 0.867 mol
Now, the number of moles of 
are calculated as follows.
No. of moles =
= 
= 1.07
Therefore, mole fraction of heptane will be calculated as follows.
Mole fraction = 
= 
= 
= 0.445
Now, we will calculate the partial pressure of heptane as follows.
= 
= 75.65 torr
Thus, we can conclude that the partial pressure of heptane vapor above this solution is 75.65 torr.
Answer:
a river that in Northeast Ohio near Cleveland that feeds into lake Erie that burned in 1969
The ionic equation will be:
<span>Mg2+(aq) + 2OH-(aq) + 2H+(aq) + 2NO3-(aq) → Mg2+(aq) + 2NO3-(aq) + 2H2O(l)
</span>And the net ionic:
<span>2OH-(aq) + 2H+(aq) → 2H2O(l)
</span>a Balanced equation would be:
<span>Mg(OH)2(aq) + 2HNO3(aq) → Mg(NO3)2 (aq) + 2H2O(l)
</span>Now thsi si so because of the standard equation which is base plus acid=Salt plus water. We need to have in mindo that Mg(OH)2 is sparingly soluble in water and is aqueous mos of the times
