Electronic transitions (i. e., absorption of uv or visible light) of the conjugated molecule butadiene can be approximated using the particle-on-a-line model, assuming one of the pi electrons can move along the whole four-carbon chain. A molecule of butadiene is found to absorb light of 207 nm corresponding to the electron being excited from the n=2 to n=3 levels. Use this to determine the length, in Angstroms, of the four-carbon chain to which the electron is confined.

2.51 Angstroms

Explanation:

For a particle in a one dimensional box, the energy level, En, is given by the expression:

En = n²π² ħ² / 2ma²

where n is the energy level, ħ²  is Planck constant divided into 2π, m is the mass of the electron ( 9.1  x 10⁻³¹ Kg ), and a is the length of the one dimensional box.

We can calculate  the change in energy, ΔE, from n = 2 to n= 3  since we know the wavelength of the transition  ( ΔE = h c/λ ) and then substitute this value for the expresion of the ΔE for a particle in a box and solve for the  length a.

λ = 207 nm x 1 x 10⁻⁹ m/nm = 2.07 x 10⁻⁷ m      ( SI units )

ΔE = 6.626 x 10⁻³⁴ J·s x  3 x 10⁸ m/s  / 2.07 x 10⁻⁷ m

ΔE   = 9.60 x 10⁻¹⁹ J

ΔE(2⇒3) = ( 3 - 2 )  x  π² x ( 6.626 x 10⁻³⁴ J·s / 2π )² / ( 2 x 9.1 x 10⁻³¹ Kg x a² )

9.60 x 10⁻¹⁹ J  =  π² x( 6.626 x 10⁻³⁴ J·s / 2π )² / ( 2 x 9.1 x 10⁻³¹ Kg x a² )

⇒ a = 2.51 x 10⁻¹⁰ m

Converting to Angstroms:

a = 2.51 x 10⁻¹⁰ m x 1 x 10¹⁰ Angstrom / m = 2.51 Angstroms

chemical energy is stored in the chemical bonds of atoms and molecules. it can only be seen when it is released in a chemical reaction. when chemical energy is released, the substance from which the energy came is often changed into an entirely different substance.

this chemical reaction releases energy in the form of light and heat. chemical energy is the potential energy stored in the arrangement of atoms within molecules. breaking chemical bonds requires energy, while forming new chemical bonds releases energy.

the atp molecule can store energy in the form of a high energy phosphate bond joining the terminal phosphate group to the rest of the molecule. in this form,energy can be stored at one location, then moved from one part of the cell to another, where it can be released to drive other biochemical reactions.

i believe it is c.) 1575 j.