Chemistry Problem-- Quantum Mechanics. Help???

Question

Microwaves cook by emitting radiation with a frequency of 2.45x109s-1. Calculate the number of photons required to raise 135.0 g H2O from 18 C to 100 C, its boiling point. Assume the heat capacity of water is constant over this temperature range and is equal to 4.2 J/g-K.

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Answer 1 · 2018-05-07T16:45:40

#sf(2.9xx10^(28))#

The heat energy required is given by:

#sf(H=mxxcxxtheta)#

#sf(H=135.0xx4.2xx82=46,494color(white)(x)J)#

The energy of 1 photon is given by:

#sf(E=hf)#

#:.##sf(E=6.63xx10^(-34)xx2.45xx10^(9)=16.2435xx10^(-25)color(white)(x)J)#

This means the no. of photons required = #sf((46,494)/(16.2435xx10^(-25))#

#sf(=2.9xx10^(28))#