Answer:
1.59 x 10⁻²⁵ J.
Explanation:
- The energy of a photon is calculated Planck - Einstein's equation:
E = h ν
, where
E is the energy of the photon,
h is Planck's constant <em>(h = 6.626 x 10
⁻³⁴ J.s)</em>
ν is the frequency of the photon
-
There is a relation between the frequency (ν
) and wave length (λ).
λ.ν = c,
where c is the speed of light in vacuum (c = 3
.0 x 10
⁸ m/s).
λ = 125 cm = 1.25 m.
<em>Now, E = h.c/λ.</em>
∴ E = h.c/λ = (6.626 x 10
⁻³⁴ J.s) (3
.0 x 10
⁸ m/s) / (1.25 m) = 1.59 x 10⁻²⁵ J.
<h3>
Answer:</h3>
Lead-205 (Pb-205)
<h3>
Explanation:</h3>
<u>We are given;</u>
We are supposed to identify its product after an alpha decay;
- Polonium-209 has a mass number of 209 and an atomic number of 84.
- When an element undergoes an alpha decay, the mass number decreases by 4 while the atomic number decreases by 2.
- Therefore, when Po-209 undergoes alpha decay it results to the formation of a product with a mass number of 205 and atomic number of 82.
- The product from this decay is Pb-205, because Pb-205 has a mass number of 205 and atomic number 82.
- The equation for the decay is;
²⁰⁹₈₄Po → ²⁰⁵₈₂Pb + ⁴₂He
- Note; An alpha particle is represented by a helium nucleus, ⁴₂He.
he total number of each of the atoms on the left and the right are the same thus the reaction equation is balanced.
<h3>What is the law of conservation of mass?</h3>
The law of conservation of mass states that, mass can neither be created nor destroyed. In view of the law of conservation of mass, the total mass of the reactants on the left-hand side must be the same as the total mass of products at the right hand side.
Thus is the total mass of the reactants and the products are not the same, it then follows that the reaction does not demonstrate the law of conservation of mass. In this case, the total number of each of the atoms on the left and the right are the same thus the reaction equation is balanced.
Learn more about conservation of mass:brainly.com/question/13383562
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Answer:
Volume is the amount of space that a substance occupies. A graduated cylinder is used to measure liquid volume. The formula used to calculate the volume of a solid object is = L x W x H
Explanation:
Answer: The molecular formula will be 
Explanation:
Molecular formula is the chemical formula which depicts the actual number of atoms of each element present in the compound.
Empirical formula is the simplest chemical formula which depicts the whole number of atoms of each element present in the compound.
Empirical weight of 
is 
Molecular mass of compound is = 132 g
Now we have to calculate the molecular formula.
The molecular formula will be=
