E = hf
c = speed of electromagnetic wave, c ≈ 3 * 10⁸ m/s,
Planck's constant h = 6.63 *10⁻³⁴ Js
h = Planck's constnat, Frquency, f = c/λ = (3*10⁸)/(488*10⁻⁹)
E = hf
E = hc/λ
E = (6.63 * 10⁻³⁴ * 3 * 10⁸) /(488 * 10⁻⁹)
Energy, E ≈ 4.0758 * 10⁻¹⁹ Joules.
Answer:
True
Explanation:
Here is an example: chemical properties include flammability, toxicity, acidity, reactivity. we observe the changes of these properties. Therefore, It's true.
The correct option is (e) 0.389 moles.
The number of moles represented by 21.7 g fe 0.389 moles.
Solution:
(21.7g) x (1mol/55.85g) = 0.389 moles
<h3>What is moles?</h3>
The mole, represented by the symbol mol, is the fundamental SI unit of material quantity. The amount of a substance determines how many elementary entities of that substance are present in an object or sample. Since the SI fundamental units were revised in 2019, the mole is now exactly defined as 6.022140761023.
<h3>Why the mole is a base unit?</h3>
The amount of a substance determines how many elementary entities of that substance are present in an object or sample. Since the SI fundamental units were revised in 2019, the mole is now exactly defined as 6.022140761023.
To learn more about moles visit:
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The fourth one is correct yw
Last option that is none of above is right answer.
