Ok so first you need to figure out the energy of ONE photon with that wavelength. Using E=hc/lambda, you get E= 1.99 * 10^-20 J/photon. Now, how many photons do you need to add up to get to one kilojoule=1000 joules? 1000J / (1.99 * 10^-20 J/photon) = approximately 5 * 10^22 photons
hope this helps
A particle is a minute fragment or quantity of matter. In the physical sciences, a particle is a small localized object to which can be ascribed several physical or chemical properties such as volume or mass. ... The term is rather general in meaning, and is refined as needed by various scientific fields.
Answer:
0.76 mole of Fe2S3.
Explanation:
Step 1:
Determination of the number of mole in 449g iron(III)bromide, FeBr3. This is illustrated below:
Mass of FeBr3 = 449g
Molar mass of FeBr3 = 56 + (80x3) = 296g/mol
Mole of FeBr3 =..?
Mole = Mass /Molar Mass
Mole of FeBr3 = 449/296
Mole of FeBr3 = 1.52 moles
Step 2:
The balanced equation for the reaction. This is given below:
2FeBr3 + 3Na2S —> 6NaBr + Fe2S3
Step 3:
Determination of the number of mole of Fe2S3 produced from the reaction of 449g ( i.e 1.52 moles) of FeBr3. This is illustrated below:
From the balanced equation above,
2 moles of FeBr3 reacted to produce 1 mole of Fe2S3.
Therefore, 1.52 moles of FeBr3 will react to produce = (1.52 x 1)/2 = 0.76 mole of Fe2S3.
Therefore, 0.76 mole of Fe2S3 is produced from the reaction.
