The bright-red color of highway safety flares comes from strontium ions in salts such as sr(no3)2 and srco3. burning a flare produces strontium ions in excited states, which then emit red photons at 606 nm and several wavelengths between 636 and 688 nm. calculate the energy (in joules per mole) of the 664 nm emission.

180309 J/mol

Explanation:

The energy given off by a proton can be expressed as:

Where h is Planck's constant, c is the speed of light and λ is the wavelenght.

Now we calculate the energy of a proton with a 664 nm emission (keep in mind that 664nm = 664x10⁻⁹m):

That is the energy of one proton of one atom, now we multiply that value by Avogadro's number to find the value in Joules per mole:

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water pollution kills aquatic life. aquatic life includes algae and other plant life that use photosynthesis. photosynthesis takes   c02 out of the air.  

c02is a greenhouse gas.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"