Answer:
Coal contains chemical potential energy
Explanation:
Chemical species are known to contain chemical energy. Chemical energy is contained in chemical bonds in a chemical substance.
Since energy can neither be created nor destroyed, energy contained in chemical bonds can be transformed from one form to another. Coal contains chemical energy.
One of the ways of generating electricity is the combination of fossil fuels. This involves the conversion of chemical energy to heat energy. The steam produced is used to turn a turbine. The turning off the turbine implies a conversion of heat to mechanical energy. The turning of the turbine now produces electrical energy.
Answer:
The enthalpy of the nitrogen-nitrogen bond in N2H4 is 162.6 kJ
Explanation:
For the reaction: N2H4(g)+H2(g)→2NH3(g), the enthalpy change of reaction is
ΔH rxn = 2 ΔHºf NH3 - ΔHºf N2H4
but we also know that the ΔH rxn is calculated by accounting the sum of number of bonds formed and bonds broken as follows:
ΔH rxn = 6H (N-H) + 4 (N-H) + 2H (H-H)
where H is the bond enthalpy .When bonds are broken H is positive, and negative when formed, in the product there are 6 N-H bonds , and in the reactants 4 N-H and 1 H-H bonds).
Consulting an appropiate reference handbook or table the following values are used:
ΔHºf (NH3) = -46 kJ/mol
ΔHºf (N2H4) = 95.94 kJ/mol
(The enthalpy of fomation of hydrogen in its standard state is zero)
H (N-H) = 391 kJ
H (H-H) = 432 kJ
H (N-N) = ?
So plugging our values:
ΔH rxn = 2mol ( -46.0 kJ/mol) - 1mol(95.4 kJ/mol) = -187.40 kJ
-187.40 kJ = 6(-391 kJ) + 4 (391 kJ) + 432 + H(N-N)
-187.40 kJ = -350 kJ + H(N-N)
H(N-N) = 162.6 kJ
Answer:
the Sun, planets, satellites, comets, asteroids and meteoroids.
Explanation:
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2,2,1,1/2 -- NOT (l too high)
3,2,1,1/2 -- Valid
2,1,-1,1/2 -- Valid
3,3,-2,-1/2 -- NOT (l too high)
1,-1,-1,-1/2 -- NOT (l too low)
4,3,3,-1/2 -- Valid
1,1,0,1/2 -- NOT (l too high)
0,2,1,1/2 -- NOT (no such thing as n = 0, l too high)
2,0,0,-1/2 -- Valid
1,0,0,1/2 -- Valid
3,2,1,0 -- NOT (cannot have ms = 0)
4,3,4,-1/2 -- NOT (ml too high)