answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
miss Akunina [59]
2 years ago
7

According to the Bohr model, the energy of the hydrogen atom is given by the equation: E = (-21.7 x 10 -19 J)/ n 2 Calculate the

wavelength of the photon emitted when the atom undergoes relaxation from the first excited state to the ground state.
Chemistry
1 answer:
Anit [1.1K]2 years ago
7 0

Answer:

91.6 nm

Explanation:

The energy of the hydrogen atom can be calculated by the emission of a photon. When an electron is excited it goes from to the next energetic level, and when it returns to its ground state, it emits a photon. Hydrogen has only one electron, which is at the level n = 1. So, the equation is given:

E = (-21.7x10⁻¹⁹J)/1²

E = -21.7x10⁻¹⁹J

The energy of the photon is the energy absorbed, and because of that is positive (the opposite of the energy released by the electron). This energy can be calculated by:

E = h*c/λ

Where h is the Planck's constant (6.626x10⁻³⁴ J.s), c is the speed of the light (3.00x10⁸ m/s), and λ is the wavelength of the photon.

21.7x10⁻¹⁹ = 6.626x10⁻³⁴ * 3.00x10⁸/λ

λ = 9.16x10⁻⁸ m

λ = 91.6 nm

You might be interested in
How many hydrogen atoms are in 11C2H6
tresset_1 [31]

Answer:

6

Explanation:

You will see H6 and the H stands for helium and the 6 is how many of that atom is there

5 0
2 years ago
Read 2 more answers
KClKCl has a lattice energy of −701 kJ/mol.−701 kJ/mol. Consider a generic salt, ABAB , where A2+A2+ has the same radius as K+,K
elena-14-01-66 [18.8K]

Explanation:

It is given that lattice energy is -701 kJ/mol.

Whereas it is known that realtion between lattice energy and radius is as follows.

               Lattice energy \propto \frac{Z_{+}Z_{-}}{r}

where,          Z_{+} = +2,    and Z_{-} = -2

Therefore, lattice energy of AB = 4 \times \text{lattice energy of KCl}

                                                    = 4 \times -701 kJ/mol

                                                    = -2804 kJ/mol

Thus, we can conclude that lattice energy of the salt ABAB is -2804 kJ/mol.

6 0
2 years ago
Three of the reactions that occur when the paraffin of a candle (typical formula C21H44) burns are as follows:
Katarina [22]

Answer and Explanation:

The 3 reactions represented are

C₂₁H₄₄ + 32O₂ -----> 21CO₂ + 22H₂O

C₂₁H₄₄ + (43/2)O₂ -----> 21CO + 22H₂O

C₂₁H₄₄ + 11O₂ -----> 21C + 22H₂O

ΔH°(C₂₁H₄₄) = -476 KJ/mol, ΔH°(O₂) = 0KJ/mol, ΔH°(CO₂) = -393.5 KJ/mol, ΔH°(CO) = -99 KJ/mol, ΔH°(H₂O) = -292.74 KJ/mol, ΔH°(C) = 0KJ/mol

ΔH°f = ΔH°(products) - ΔH°(reactants)

For reaction 1,

ΔH°(products) = 21(ΔH°(CO₂)) + 22(ΔH°(H₂O)) = 21(-393.5) + 22(-292.74) = -14703.78 KJ/mol

ΔH°(reactants) = ΔH°(C₂₁H₄₄) = -476 KJ/mol

ΔH°f = -14703.78 - (-476) = - 14227.78 KJ/mol

For reaction 2,

ΔH°(products) = 21(ΔH°(CO)) + 22(ΔH°(H₂O)) = 21(-99) + 22(-292.74) = -8519.28 KJ/mol

ΔH°(reactants) = ΔH°(C₂₁H₄₄) = -476 KJ/mol

ΔH°f = -8519.28 - (-476) = - 8043.28 KJ/mol

For reaction 3,

ΔH°(products) = 21(ΔH°(C)) - 22(ΔH°(H₂O)) = 21(0) + 22(-292.74) = -6440.28 KJ/mol

ΔH°(reactants) = ΔH°(C₂₁H₄₄) = -476 KJ/mol

ΔH°f = -6440.28 - (-476) = - 5968.28 KJ/mol

b) To obtain the q for the combustion of 254g of paraffin, we convert the mass to moles.

Number of moles = mass/molar mass; molar mass of C₂₁H₄₄ = 296 g/mol

Number of moles = 254/296 = 0.858 mole

heat of reaction for the combustion of C₂₁H₄₄ when it is complete combustion, q = ΔH°(complete combustion, i.e. reaction 1) × number of moles = -14227.78 × 0.858 = -12207.435 KJ/mol

c) 8% of the mass of C₂₁H₄₄ undergoes incomplete combustion = 8% × 254 = 20.32g, in number of moles = 20.32/296 = 0.0686 mole

5% of the mass of C₂₁H₄₄ becomes soot = 5% × 254 = 12.7g, in number of moles = 12.7/296 = 0.0429 mole

The remaining paraffin undergoes complete combustion = 87% of 254 = 220.98g, in number of moles = 220.98 = 0.747 mole

q = sum of all the heat of reactions = (0.747 × -14227.78) + (0.0686 × -8043.28) + ( 0.0429 × -5968.28) = -11435.377 KJ

QED!!!

8 0
2 years ago
Cylinders of compressed gas are typically filled to a pressure of 200 bar. For oxygen, what would be the molar volume at this pr
mars1129 [50]

Answer:

a

 V  =   0.124 \ Liters

b

V  =  0.112 \  Liters

Explanation:

From the question we are told that

  The pressure of compressed gas is P  =  200 \  bar = \frac{200}{1.013}=  197.4 \ atm

  The  temperature is  T  =  25^oC =  25 + 273 = 298 \  K

Generally the perfect gas equation is mathematically represented as

     PV =  nRT

substituting 0.08206 L-atm/mol-K  for R and  1 mole for n

We have that

     V  =  \frac{1 *  0.08206 * 298 }{ 197.4}

       V  =   0.124 \ Liters

Generally the van der Waals equation is mathematically represented as

       nRT  =  [P + \frac{n^2 * a }{V^2 } ][V - nb]

=>1 *  0.08206 *298  =  [197.4 + \frac{1^2 *  1.364}{V^2 } ][V - 1 * 3.19 * 10^{-2}]

=>    V  =  0.112 \  Liters

7 0
2 years ago
The density of a 50% solution of naoh is 1.525 g/ml. what volume of a solution that is 50% by weight naoh is required to make 0.
jolli1 [7]
We consider that the 50% given in this item is by volume. Molarity is the unit of concentration that takes into account the number of moles of the solute and the number of moles of the substance.

      number of moles of NaOH = (0.1 moles / L)(0.4 L)
                      n = 0.04 moles of NaOH

If we are to take the basis of 1 mL of 50% NaOH solution, 
  
                  (1 mL solution)(1.525 g/mL)(0.50) = 0.7625 g
The number of moles is,
                  0.7625 g NaOH x (1 mol / 40 g) = 0.01906 moles of NaOH

                volume of solution required = (0.04 moles of NaOH)(1 mL solution / 0.01906 moles of NaOH)
                 
                 volume of solution required = 2.09 mL

Answer: 2.09 mL
3 0
2 years ago
Other questions:
  • At higher elevations, the boiling point of water decreases, due to the decrease in atmospheric pressure. As a result, what could
    7·1 answer
  • Explain why a propane torch is lit inside a hot air balloon during preflight preparations. Which gas law applies?
    15·2 answers
  • Alexandra decides to climb Mt. Krumpett, which is 5000 m high. She determines that this will require a total of 1350 kcal of ene
    15·1 answer
  • What mass of CaSO3 must have been present initially to produce 14.5 L of SO2 gas at a temperature of 12.5°C and a pressure of 1.
    11·1 answer
  • **PLATO QUESTION, PLEASE ANSWER CORRECTLY**
    9·1 answer
  • If 4.00 g of gallium is reacted with 5.50 g of arsenic how many grams of the excess reactant are left at the end of the reaction
    11·2 answers
  • Use the following half-reactions to design a voltaic cell: Sn4+(aq) + 2 e− → Sn2+(aq) Eo = 0.15 V Ag+(aq) + e−→ Ag(s) Eo = 0.80
    12·1 answer
  • Lastly, Snape thinks we should try one more calculation. What is the retention factor if the distance traveled by the solvent fr
    8·1 answer
  • During an experiment, the percent yield of calcium chloride from a reaction was 82.38%. Theoretically, the expected amount shoul
    6·1 answer
  • When 1.04g of cyclopropane was burnt in excess oxygen in a bomb calorimeter, the temperature rose by 3.69K. The total heat capac
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!