Achieve#5

[asheagg3I]

Can somebody help me with Achieve hw #5? I'm not sure how to find the number of photons....

[Divya Hebbar]

First, you need to know the amount of energy it takes to melt the ice. You can find this by multiplying the mass of the ice they give you with the enthalpy of fusion, which is 333.6J. Next you need to find the energy of one photon using the wavelength they give you and the equation E= hc/wavelength. Now just divide the energy needed to melt the ice by the energy of one photon to get the number of photons.

[Anton Truskovsky 2K]

1. The question tells us to use the enthalpy of fusion of water provided in the table (333.6J/g).
2. Calculate how many Joules of energy are needed to 449g of ice (333.6J/g x 449g)
3. Calculate the energy of the photons of incident light (E=hc/λ)
4. Divide the total Joules of energy needed (Step 2) by the energy per photon (Step 3) to calculate how many photons it takes to melt the quantity of ice provided.