1answer.
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
Rzqust [24]
3 years ago
15

An atom (not a hydrogen atom) absorbs a photon whose associated wavelength is 300 nm and then immediately emits photon whose ass

ociated wavelength is 640 nm. How much net energy is absorbed by the atom in this process?
Chemistry
1 answer:
KIM [24]3 years ago
6 0

Answer:

The net energy is 2.196 eV

Explanation:

Basically, the energy of an atom increases when it absorbs a photon. In addition, the wavelength of the emitted photon is longer such that the atom absorbed a net energy in the process.

Using:

ΔE = h*c*(1/λ_{1} - 1/λ_{2})

where:

ΔE is the net energy in eV (electron-volt). 1 eV is equivalent to 1.602*10^{-19} J.

h = 4.135*10^{-15} eVs

c = 3*10^{8} m/s

λ_{1} = 300 nm = 300*10^{-9} m

λ_{2} = 640 nm = 640*10^{-9} m

Thus:

ΔE = 4.135*10^{-15} eVs*3*10^{8} m/s*(\frac{1}{300*10^{-9}m } }-\frac{1}{640*10^{-9}m })

ΔE = 4.135*10^{-15}*3*10^{8}*1.77*10^{6} eV = 2.196 eV

You might be interested in
Which of the following is true for compounds?
soldi70 [24.7K]
Compound are formed by two or more elements chemically combined. For example: H^2O is the water formula, this is a compound because you two elements which are Hydrogen and Oxygen and together they form a compound. The (^2) is the amount of atoms the formula has, in this case Hydrogen has two atoms and Oxygen is neutral.
4 0
3 years ago
Draw the product that valine forms when it reacts with excess CH3CH2OH and HCl followed by a wash with aqueous base.
-BARSIC- [3]

Answer:

Product: ethyl L-valinate

Explanation:

If we want to understand what it is the molecule produced we have to an<u>alyze the reagents</u>. We have valine an <u>amino acid</u>, in this kind of compounds we have an <em>amine group</em> (NH_2) and a <em>carboxylic acid</em> group (COOH).  Additionally, we have an <u>alcohol </u>(CH_3CH_2OH) in the presence of HCl (a <u>strong acid</u>) in the first step, and a base (OH^-).

When we have an acid and an alcohol in a vessel we will have an <u>esterification reaction</u>. In other words, an ester is produced. As the <em>first step,</em> the oxygen in the C=O (in the carboxylic acid group) would be protonated. In the <em>second step</em>, the ethanol attacks the carbon in the C=O of the carboxylic acid group producing a new bond between the oxygen in the ethanol and the carbon in the carboxylic acid. In <em>step 3</em>, a proton is transferred to produce a better leaving group (H_2O). In <em>step 4</em>, a water molecule leaves the main structure to produce again the double bond C=O. <em>Finally</em>, a base (OH^-) removes the hydrogen from the C=O bond to produce ethyl L-valinate

See figure 1

I hope it helps!

7 0
3 years ago
HELP QUICK ASSESMENT
ehidna [41]

Answer:

MAGNESIUM

Explanation:

7 0
2 years ago
Read 2 more answers
If 12.5 grams of strontium hydroxide is reacted with 150 mL of 3.5 M carbonic acid, identify the limiting reactant.
kiruha [24]

Answer:

Sr(OH)₂ will be the limiting reagent.

Explanation:

First of all, you should know the following balanced chemical equation:

2 H₂CO₃ + 2 Sr(OH)₂ → 4 H₂O + Sr₂(CO₃)₂

The balanced equation is based on the Law of Conservation of Mass, which says that matter cannot be created or destroyed. Therefore, the number of each type of atom on each side of a chemical equation must be the same.      

The limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.

To determine the limiting reagent, it is possible to use the reaction stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction). By stoichiometry the following amounts in moles react:

  • strontium hydroxide: 2 moles
  • carbonic acid: 2 moles

Now, you know the following masses of the elements:

  • Sr: 87.62 g/mole
  • O: 16 g/mole
  • H: 1 g/mole

So the molar mass of strontium hydroxide is:

Sr(OH)₂= 87.62 g/mole + 2*(16 g/mole + 1 g/mole)= 121.62 g/mole

You apply the following rule of three, if 121.62 grams of hydroxide are present in 1 mole, 12.5 grams in how many moles are they?

moles of strontium hydroxide=\frac{12.5 grams*1 mole}{121.62 grams}

moles of hydroxide= 0.103 moles

On the other hand, you have 150 ml of 3.5 M carbonic acid. Since molarity is the concentration of a solution expressed in the number of moles dissolved per liter of solution, you can apply the following rule of three: if in 1 L there are 3.5 moles of carbonic acid, in 0.150 L (being 1 L = 1000 mL, 0.150 L = 150 mL) how many moles of acid are there?

molesofcarbonicacid=\frac{0.150 L*3.5 moles}{1 L}

moles of carbonic acid= 0.525 moles

Finally, to calculate the limiting reagent, you can use a simple rule of three as follows: if by stoichiometry 2 mole of strontium hydroxide reacts with , how much moles of carbonic acid will be needed if 0.103 moles of strontium hydroxide react?

molesofcarbonicacid=\frac{0.103 moles of strontium hydroxide*2 moles of carbonic acid}{2 moles of strontium hydroxide}

moles of carbonic acid= 0.103 moles

But 0.525 moles are available. Since more moles are available than you need to react with 0.103 moles of strontium hydroxide, <u><em>Sr(OH)₂ will be the limiting reagent.</em></u>

7 0
3 years ago
What would be the oxidation and reduction half reactions for this equation?
Sedbober [7]

Answer:

Fe(s) → Fe²⁺(aq) + 2e⁻   OXIDATION

Mg²⁺(aq) + 2e⁻ → Mg(s)   REDUCTION

Explanation:

The redox reaction is: MgCl₂(aq) + Fe(s) → FeCl₂(aq) + Mg(s)

We need to know that elements in ground state have 0 as the oxidation state.

Iron in the reactants, and Mg in the products

In the magnessium chloride, the Mg acts with+2, so the oxidation state has decreased → REDUCTION

In the iron(II) chloride, the Fe acts with +2, so the oxidation statehas increased → OXIDATION

The half reactions are:

Fe(s) → Fe²⁺(aq) + 2e⁻   OXIDATION

Mg²⁺(aq) + 2e⁻ → Mg(s)   REDUCTION

5 0
3 years ago
Other questions:
  • If the Earth moved farther away from the sun, which of these would probably happen?
    9·2 answers
  • What particles contribute to the mass of an atom?
    13·2 answers
  • The atomic number of nitrogen is 7. How many protons,neutrons ,and electrons make up an atom of nitrogen -15
    8·1 answer
  • The properties of matter depend on the types of atoms a substance is made of.<br> true of false?
    13·2 answers
  • The reason that it is (mostly) correct to generalize that ionic bonds will form between a metal and a nonmetal is that _____.
    13·1 answer
  • Atoms are composed of subtomatic particles called
    8·1 answer
  • Which statement is not true about the periodic table?
    10·1 answer
  • Please please do it because i need an answer.
    9·1 answer
  • A force that is opposite to motion of a falling object?
    12·1 answer
  • How do secretions of apocrine glands differ from those of the eccrine sweat glands
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!