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.

1185 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-05-07T16:45:40

$2.9 \times 10^{28}$ $sf(2.9xx10^(28))$

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 = $sf((46,494)/(16.2435xx10^(-25))$

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