Units
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Units
I'm a little confused on how the units cancel out for the equation E= hv. Planck's constant is represented in J x s while frequency is represented in Hertz. How does the multiplication of Hertz with Joules and seconds end up canceling out to just have E in units of Joules?
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Re: Units
The unit "hertz" means 1/seconds, so when you multiply J x s by Hz = 1/s, the seconds cancel out and you're left with J.
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Re: Units
hertz is equivalent to per second (1 s^-1) so in the equation E=hv, h has units of J x s and v has units of 1/s so when you multiply the two cancel out to get J which is the unit for energy
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Re: Units
Frequency is represented by Hz (or 1/s) when doing the calculations the h units cancel with the seconds and J is left. Which shows the units for energy is J, as said before in the other replies.
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Re: Units
Since hertz is 1/second when you multiply (J x second)(1/second) the seconds cancel out which leads to J.
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Re: Units
I like to write it out like in dimensional analysis. It will help you follow your work, and you can clearly see what can be cancelled out. Since 1 Hertz is 1/s, if you multiply it with Jxs, the s will be cancelled out, leaving just s. I suggest writing out the units in your work for dimensional analysis throughout chemistry problems such as converting moles to grams and comparing molar ratios.
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