Answer:
n = 2.208x10¹⁸ photons
Explanation:
The energy of a photon( an elementary particle) is given by the equation:
E = nxhxf
Where n is the number of photons, h is plank constant (6,62x10⁻³⁴ J.s), and f is the frequency. Knowing that the power level is 0.120mW (1.2x10⁻⁴ W), the energy in J, for a time of 78 min (4680 s)
E = 1.2x10⁻⁴x4680 = 0.5616 J
The frequency of a photon is its velocity ( c= 3x10⁸ m/s) divided by its wavelength, which is 780 nm = 780x10⁻⁹ m
f = 3x10⁸/780x10⁻⁹
f = 3.846x10¹⁴ s⁻¹
Then, the number of photons is:
0.5616 = nx6,62x10⁻³⁴x3.846x10¹⁴
n = 2.208x10¹⁸ photons.
Answer:
If we use a thick foil, then more α particles would bounce back, and no idea about the location of positive mass in the atom would be available with such certainty.
Cobalt(II) has a charge of 2+
Phosphate has a charge of 3-
Because it's an ionic compound, you will need to take the charge and make them subscripts.
The formula for cobalt(II) phosphate is
Co₃(PO₄)₂
Your answer is
When the value of Ksp = 3.83 x 10^-11 (should be given - missing in your Q)
So, according to the balanced equation of the reaction:
and by using ICE table:
Ag2CrO4(s) → 2Ag+ (Aq) + CrO4^2-(aq)
initial 0 0
change +2X +X
Equ 2X X
∴ Ksp = [Ag+]^2[CrO42-]
so by substitution:
∴ 3.83 x 10^-11 = (2X)^2* X
3.83 x 10^-11 = 4 X^3
∴X = 2.1 x 10^-4
∴[CrO42-] = X = 2.1 x 10^-4 M
[Ag+] = 2X = 2 * (2.1 x 10^-4)
= 4.2 x 10^-4 M
when we comparing with the actual concentration of [Ag+] and [CrO42-]
when moles Ag+ = molarity * volume
= 0.004 m * 0.005L
= 2 x 10^-5 moles
[Ag+] = moles / total volume
= 2 x 10^-5 / 0.01L
= 0.002 M
moles CrO42- = molarity * volume
= 0.0024 m * 0.005 L
= 1.2 x 10^-5 mol
∴[CrO42-] = moles / total volume
= (1.2 x 10^-5)mol / 0.01 L
= 0.0012 M
by comparing this values with the max concentration that is saturation in the solution
and when the 2 values of ions concentration are >>> than the max values o the concentrations that are will be saturated.
∴ the excess will precipitate out
sulphate ions and 
ammonium ions are present in a 0.310 mole sample of (NH₄)₂SO₄ .
<h3>
What is a mole?</h3>
The International System of Units uses the mole (symbol: mol) as the unit of material quantity (SI). How many elementary entities of a particular substance are present in an object or sample is determined by the quantity of that material.
There are precisely 6.022140761023 elementary entities in a mole. An elementary entity can be an atom, a molecule, an ion, an ion pair, or a subatomic particle like an electron depending on what the substance is.
How this is calculated?
- The subscripts next to each atom allow you to find the number of moles of each element in the compound.
- Then, in every mole of (NH₄)₂SO₄ there are:
2 moles of ammonium (NH₄) ions and 1 mole of sulfate (SO₄) ions.
- Number of sulphate ions:
To know more about moles, refer:
brainly.com/question/19964502
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