We first calculate the energy contained in one photon of this light using Planck's equation:
E = hc/λ
E = 6.63 x 10⁻³⁴ x 3 x 10⁸ / 590 x 10⁻⁹
E = 3.37 x 10⁻²² kJ/photon
Now, one mole of atoms will excite one mole of photons. This means that 6.02 x 10²³ photons will be excited
(3.37 x 10⁻²² kJ/photon) x (6.02 x 10²³ photons / mol)
The energy released will be 202.87 kJ/mol
The answer is (3) 3. The calculation rule of significant figures is when multiplication and division, the significant figures of result is equal to the least of the numbers involved. The significant figure of 2.70 and 80.01 is 3 and 4.
Answer:- 324.3 grams.
Solution:- We have been given with 6.0 moles of nitrous acid and asked to calculate it's grams. Moles to grams is a unit conversion and for doing this conversion we multiply the given moles by the molar mass of the compound.
Molar mass is the formula mass and to calculate this the atomic masses of each atom are multiplied by their respective subscripts that is the number of the atom in the compound .
For example,
has one nitrogen atom and one oxygen atom. So, the molar mass of this is = atomic mass of N + 2(atomic mass of O)
= 14 + 2(16)
= 14 + 32
= 46 gram per mol
gram per mol is the unit of molar mass. So, the molar mass of
is 46 grams per mol.
Let's calculate the molar mass of nitrous acid using the same concept.
molar mass of [
= 1 + 14 + 2(16)
= 1 + 14 + 32
= 47 grams per mol
Now, 6.9 moles of nitrous acid could easily be converted to grams as:

= 324.3 g
Hence, the mass of 6.9 moles of nitrous acid is 324.3 grams.
AN element is composed from atoms with the same number of protons,
A compound contain two or more different elements