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Mamont248 [21]
2 years ago
10

What minimum frequency of light is required to ionize boron?

Chemistry
1 answer:
Nadusha1986 [10]2 years ago
3 0

Answer:

frequency  = 8.22 x 10¹⁴ s⁻¹

Explanation:

An electron's positional potential energy while in a given principle quantum energy level is given by Eₙ = - A/n² and A = constant = 2.18 x 10⁻¹⁸j. So to remove an electron from the valence level of Boron (₅B), energy need be added to promote the electron from n = 2 to n = ∞. That is, ΔE(ionization) = E(n=∞) - E(n=2) = (-A/(∞)²) - (-A/(2)²) = [2.18 x 10⁻¹⁸j/4] joules = 5.45 x 10⁻¹⁹ joules.

The frequency (f) of the wave ionization energy can then be determined from the expression ΔE(izn) = h·f; h = Planck's Constant = 6.63 x 10⁻³⁴j·s. That is:

ΔE(izn) = h·f => f = ΔE(izn)/h = 5.45 x 10⁻¹⁹ j/6.63 x 10⁻³⁴ j·s = 8.22 x 10¹⁴ s⁻¹

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Zn +
saul85 [17]

Answer:

1. Theoretical yield = 2.03g

2. Actual yield 1.89g

Explanation:

Let us write a balanced equation. This is illustrated below:

Zn + 2HCI —> ZnCl2 + H2

Molar Mass of HCl = 1 +35.5 = 36.5g/mol

Mass of HCl from the balanced equation = 2 x 36.5 = 73g

Molar Mass of H2 = 2x1 = 2g/mol

1. From the equation,

73g of HCl produced 2g of H2.

Therefore, 74g of HCl will produce = (74 x 2)/73 = 2.03g

Therefore, theoretical yield = 2.03g

2. %yield = 93%

Theoretical yield = 2.03g

Actual yield =?

%yield = Actual yield /Theoretical yield x100

Actual yield = %yield x theoretical yield

Actual yield = 93% x 2.03 = (93/100)x2.03 = 1.89g

Actual yield =1.89g

4 0
3 years ago
A children's liquid cold medicine has a specific gravity of 1.23. If a child is to take 1.5 tsp in a dose, what is the mass (in
julia-pushkina [17]

Assume 1 tsp is approximately can hold 5 mL liquid.

Given the dose of medicine = 1.5 tsp

Converting 1.5 tsp to mL:

1.5 tsp * \frac{5 mL}{1 tsp} = 7.5 mL

Given the specific gravity of the medicine = 1.23

That means density of the medicine with respect to water will be 1.23

As the density of water is 1 g/mL

We can take density of the medicine to be 1.23 g/mL

Calculating the mass of medicine in grams:

7.5 mL * \frac{1.23 g}{mL} =9.225 g

9.225 g medicine is present in one dose.

3 0
2 years ago
Read 2 more answers
Which organelle’s function is NOT correct?
Scorpion4ik [409]
The answer is the last one, “The cell membrane is the only source of support and structure in plant and animal cells.” That is false because plant cells have a cell wall and cell membrane while animal cells only have a cell membrane.

Hope this helps:)
5 0
2 years ago
A chemical equation is shown:
taurus [48]

 The number  of  oxygen atoms  are 6  atoms


  <u><em>Explanation</em></u>

According to the law of mass conservation the number of  reactant atoms   is equal to  number  of product atoms.

For  given equation  to  obey  the  law of mass  conservation  it need to be balanced as below

4 Al + 3 O₂ → 2 Al₂O₃

Al₂O₃  is the  product,therefore the number of oxygen atom

= coefficient  in front  of   Al₂O₃   ×  subscript  of O

=2 x 3  = 6 atoms

7 0
3 years ago
Read 2 more answers
How many atoms are in 73.9g of potassium oxide
denis-greek [22]

Answer: 4.69(10)^{23} atoms

Explanation:

Firstly, we have to find the Molecular mass of potassium oxide (K_{2}0):

K atomic mass: 39 u

O atomic mass: 16 u

K_{2}O molecular mass: 39(2) g/mol+16g/mol=94 g/mol

This means that in 1 mole of K_{2}O there are 94 g and we need to find how many moles there are in 73.9 g K_{2}O:

1 mole of K_{2}O-----94 g of K_{2}O

X-----73.9 g of K_{2}O

X=\frac{(73.9 g)(1 mole)}{94 g}

X=0.78 mole This is the quantity of moles in 73.9 g of potassium oxide

Now we can calculate the number of atoms in 73.9 g of potassium oxide by the following relation:

N_{atoms}=(X)(N_{A})

Where:

N_{atoms} is the number of atoms in 73.9g of potassium oxide

N_{A}=6.0221(10)^{23}/mol is the Avogadro's number, which is determined by the number of particles (or atoms) in a mole.

Then:

N_{atoms}=(0.78 mole)(6.0221(10)^{23}/mol)

N_{atoms}=4.69(10)^{23} atoms This is the quantity of atoms in 73.9g of potassium oxide

6 0
3 years ago
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