The
equation for the photosynthesis reaction in which carbon dioxide and water
react to form glucose is .
The hear reaction is the difference between the bond dissociation energies in
the products and the bond dissociation energies of the reactants
The
reactant molecules have 12 C = O, 12 H - O bonds while the product molecules
have 5 C - C, 7 C – O, 5 H – O, and 6 O = O bonds. The average bond
dissociation energies for the bonds involved in the reaction are 191 for C = O,
112 for H – O, 83 C –C, 99 C – H, 86 C – O, 119 O = O.
Substitute
the average bond dissociation energies in the equation for and
calculate as follows
=
[12 (C=O) + 12 (H-O)] – [5(C-C) + 7(C-H) + 7 (C-O) + 5(H-O) + 6(O=O)]
=
[12x191 kcal/mol + 12x112 kcal//mol] – [5x83 kcal/mol + 7x99 kcal/mol + 7x86
kcal/mol + 5x112 kcal/mol + 6x119 kcal/mol]
=
3636 kcal/mol – 2984 kcal/mol = 652 kcal/mol x 4.184 Kj/1kcal = 2.73x10^3 kJ/mol
So,
enthalpy change for the reaction is 652 kcal/mol or 2.73x10^3 kJ/mol
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Answer:
Photon of light
Explanation:
According to Bohr's model of the atom, electrons in atoms are found in specific energy levels. These energy levels are called stationary states, an electrons does not radiate energy when it occupies any of these stationary states.
However, an electron may absorb energy and move from one energy level or stationary state to another. The energy difference between the two energy levels must correspond to the energy of the photon of light absorbed in order to make the transition possible.
Since electrons are generally unstable in excited states, the electron quickly jumps back to ground states and emits the excess energy absorbed. The frequency or wavelength of the emitted photon can now be measured and used to characterize the transition. This is the principle behind many spectrometric and spectrophotometric methods.
Answer:
that's because....
group 1 (e.g Na, K) those tend to lose one electron to gain noble gas electron configuration.
they can achieve that by just losing one electron from their outer shell.
as you go down the group 1, element gets bigger in size, which means there is more space between nucleus (which is in center of atom) and electron of outer shell. the more far away they are the less attraction force between them.
so its easier for potassuim to lose one electron than for lithuim.
so that means potassium will easily give up 1 electron to react with non metal or other element therefore it is more reactive than lithuim
but in case of non metal, the opposite happens but simple to understand.
as you go down the group 7 (halogen- Cl, Br, I) element will get bigger therefore force between nucleus and outer electron is getting smaller. they have to gain 1 electron in order to fill the outer shell (to gain noble gas electron configuration.)
as florine is more smaller in size than clorine it is more reactive because florine has more tendency to pull extra electron from metal or other element towards its side. so it easily gain 1 electron to react.
