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Ivan
1 year ago
14

A ground state hydrogen atom absorbs a photon of light having a wavelength of 93.7 nm.93.7 nm. What is the final state of the hy

drogen atom? Values for physical constants can be found in the Chempendix.
Chemistry
1 answer:
sammy [17]1 year ago
7 0

Answer:

5

Explanation:

Given that the formula is;

1/λ= R(1/nf^2 - 1/ni^2)

λ = 93.7 nm or 93.7 * 10^-9 m

R= 1.097 * 10^7 m-1

nf = ?

ni = 1

From;

ΔE = hc/λ

ΔE = 6.63 * 10^-34 * 3* 10^8/93.7 * 10^-9

ΔE = 21 * 10^-19 J

ΔE = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

21 * 10^-19 J = -2.18 * 10^-18 J (1/nf^2 - 1/ni^2)

21 * 10^-19/-2.18 * 10^-18 = (1/nf^2 - 1/1^2)

-0.963 = (1/nf^2 - 1)

-0.963 + 1 = 1/nf^2

0.037 = 1/nf^2

nf^2 = (0.037)^-1

nf^2 = 27

nf = 5

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2 years ago
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Twenty-seven milliliters of an acid with an unknown concentration are titrated with a base that has a concentration of 0.55 M. T
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It should be 0.25 M. Use the formula C1*V1=C2*V2, for those values, as it is right when it changed colour. Remember to change the if those are not the same (but in your case it is, so no need this time). 

C1*V1=C2*V2
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4 0
2 years ago
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A 25.0-mL sample of a 1.20 M potassium chloride solution is mixed with 15.0 mL of a 0.900 M lead(II) nitrate solution and this p
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Answer:

Limiting reagent = lead(II) nitrate

Theoretical yield = 3.75435 g

% yield = 65.26 %

Explanation:

Considering:

Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}

Or,

Moles =Molarity \times {Volume\ of\ the\ solution}

Given :

For potassium chloride :

Molarity = 1.20 M

Volume = 25.0 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 25.0×10⁻³ L

Thus, moles of potassium chloride :

Moles=1.20 \times {25.0\times 10^{-3}}\ moles

<u>Moles of potassium chloride  = 0.03 moles</u>

For lead(II) nitrate :

Molarity = 0.900 M

Volume = 15.0 mL

The conversion of mL to L is shown below:

1 mL = 10⁻³ L

Thus, volume = 25.0×10⁻³ L

Thus, moles of lead(II) nitrate :

Moles=0.900 \times {15.0\times 10^{-3}}\ moles

<u>Moles of lead(II) nitrate  = 0.0135 moles</u>

According to the given reaction:

2KCl_{(aq)}+Pb(NO_3)_2_{(aq)}\rightarrow PbCl_2_{(s)}+2KNO_3_{(aq)}

2 moles of potassium chloride react with 1 mole of lead(II) nitrate

1 mole of potassium chloride react with 1/2 mole of lead(II) nitrate

0.03 moles potassium chloride react with 0.03/2 mole of lead(II) nitrate

Moles of lead(II) nitrate = 0.015 moles

<u>Limiting reagent is the one which is present in small amount. Thus, lead(II) nitrate is limiting reagent. (0.0135 < 0.015)</u>

The formation of the product is governed by the limiting reagent. So,

1 mole of lead(II) nitrate gives 1 mole of lead(II) chloride

0.0135 mole of lead(II) nitrate gives 0.0135 mole of lead(II) chloride

Molar mass of lead(II) chloride = 278.1 g/mol

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<u>Theoretical yield = 3.75435 g</u>

Given experimental yield = 2.45 g

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Answer:

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If six A atoms form six product molecules, each molecule can contain only one A atom.

The formula of the product is ABₙ.

If n = 1, we need six atoms of B.

If n = 2, we need 12 atoms of B. However, we have only eight atoms of B, so the formula of the product must be AB.

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Explanation:

Credit goes to @znk

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Answer: the mass number of the daugther atom is 232,


Explanation:


1) Alpha (α) decay is a nuclear reaction in which a nucleus (parent's nucleus) emits an alpha (α) particle and leads to a different atom (daughter atom).


2) The alpha (α) particle is a nucleus of helium atom, i,e, a nucleus with two protons and two neutrons. The symbol used for the α particles is <em>⁴₂He</em>, where the superscript 4 indicates the mass number (2 protons + 2 neutrons = mass number 4), and the subscript 2 indicates the atomic number (number of protons).


3) Then, to determine the mass number of the daughter atom you just need to do a mass number balance:


mass number of the parent atom = mass number of the daugther atom + mass number of the α particle.


The mass number of the radioactive (parent) atom is 90 protons + 142 neutrons = 232.


∴ 232 = x + 4 ⇒ x = 232 - 4 = 228 ← answer.


The full equation may help you to have a wider vision of the problem:


²³²₉₀ X → ⁴₂ He + ²²⁸₈₈ Y

Note this:

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  • 90 = 2 + 88 (this is an atomic number balance)
  • X is the parent atom, and Y is the daughter atom
  • You can use a periodic table to determine the identity of the unknown atoms (using the atomic numbers).
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2 years ago
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