Answer:
ΔE = 73 J
Explanation:
By the first law of thermodynamics, the energy in the system must conserved:
ΔE = Q - W
Where ΔE is the internal energy, Q is the heat flow (positive if it's absorbed by the system, and negative if the system loses heat), and W is the work (positive if the system is expanding, and negative if the system is compressing).
So, Q = + 551 J, and W = + 478 J
ΔE = 551 - 478
ΔE = 73 J
Answer:
B.
Explanation:
This is physical change as the popcorn has expanded in size.
Answer:
H2O> NH3>CH4
Explanation:
Now let us look at the issue of the approximate bond angles of each specie;
H2O- 104°
NH3 - 107°
CH4 - 109°
We can see that both species are based on a tetrahedron on the basis of electron pair geometry. How ever, we must also remember that lone pairs cause more repulsion around the central metal atom atom and distort the bond angles. Thus, in the presence of lone pairs, molecules depart from the expected shape predicted by valence shell electron pair repulsion theory. Hence, the repulsion of lone pairs in water (2 lone pairs) is greater than the repulsion in ammonia (1 lone pair) and repulsion in ammonia is greater than the repulsion in methane (no lone pair).
