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HELP! Chemistry Problem (determining energy for different kinds of light)?
Determine the energy of 1.60 mol of photons for each of the following kinds of light. (Assume three significant figures.)
a) infrared radiation (1520 nm )
b) visible light (500 nm )
c) ultraviolet radiation (135 nm )
Please show how you did it, I have no idea how to do this lol
1 Answer
- Dr WLv 71 year agoFavorite Answer
use this equation..
.. E = hf = hc/L
where
.. E = energy per photon
.. h = plancks constant = 6.626x10^-34 J * sec
.. f = frequency... units are 1 / sec...... and fyi.. 1/sec = 1 hz
.. c = speed of light = 3.00x10^8 m / sec
.. L = wavelength...... make sure the units are consistent
*********
(a)..
.. 1.60 mol .. .6.022x10^23 ... (6.626x10^-34 J*sec) * (3.00x10^8 m/sec).. 1kJ
---- ---- ---- x ---- ----- ---- --- x ----- --- x---- ---- ---- ---- ---- ---- ---- ---- ----- x ---- -- = 126 kJ
.. .... .1 .... ..... .... 1 mol ... .. ..... .... ... (1520nm * 1m / 10^9 nm).. ... ... .. .. 1000J
(b)..
.. 1.60 mol .. .6.022x10^23 ... (6.626x10^-34 J*sec) * (3.00x10^8 m/sec).. 1kJ
---- ---- ---- x ---- ----- ---- --- x ----- --- x---- ---- ---- ---- ---- ---- ---- ---- ----- x ---- -- = 383 kJ
.. .... .1 .... ..... .... 1 mol ... .. ..... .... ... (500nm * 1m / 10^9 nm).. ... ... .. .. 1000J
(c)..
.. 1.60 mol .. .6.022x10^23 ... (6.626x10^-34 J*sec) * (3.00x10^8 m/sec).. 1kJ
---- ---- ---- x ---- ----- ---- --- x ----- --- x---- ---- ---- ---- ---- ---- ---- ---- ----- x ---- -- = 1,420 kJ
.. .... .1 .... ..... .... 1 mol ... .. ..... .... ... (135nm * 1m / 10^9 nm).. ... ... .. .. 1000J
