Finally, examine the atomic spectrum below. Estimate the wavelength of each spectral line, then use that collection of wavelengths to try and
determine the identity of the element using the internet. This is the
kind of work a graduate student in chemistry might be assigned to do.
400
450
500
650
700
750
550 600
wavelength (nm)
Identity of the element

i think it's c. i'm not sure but i think so.

28528289 29823282 8298232 39858

option c: 1605.1 kj

the balanced chemical reaction for combustion of methane is as follows:

here, enthalpy formation of is -74.7 kj/mol, 0 kj/mol, -393.5 kj/mol and -241.82 kj/mol respectively.

the heat released or can be calculated as follow:

putting the values,

thus, heat released by combustion of 1 mol of methane is 802.54 kj/mol. thus, for 2 mol, heat released will be:

therefore, heat released by the combustion of 2 mol of methane is 1605.1 kj.