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
bogdanovich [222]
3 years ago
7

The bright-red color of highway safety flares comes from strontium ions in salts such as Sr(NO3)2 and SrCO3. Burning a flare pro

duces strontium ions in excited states, which then emit red photons at 606 nm and several wavelengths between 636 and 688 nm. Calculate the energy (in Joules per mole) of the 649 nm emission.
Chemistry
1 answer:
Luden [163]3 years ago
3 0

Answer:

E = 1.8 x 10⁵ J/mol

Explanation:

We are being asked the enery per mol for an emission line corresponding to 649 nm.

The energy of a photon is given by the porduct of Planck's contant times the frequency of the radiation,

                       E = hν

We also know that  the frequency is given by

ν = c/λ

where c is the speed of light (3 x 10 ^8 m/s) and λ is 649 nm given in the problem. Therefore the energy per photon will be given by

E= hc/λ = 6.626 x 10⁻³⁴Js x 3 x 10 ^8 m/s/ 649 x 10 ⁻⁹ m

E = 3.1  x 10 ⁻¹⁹ J/ photon

(Note the wavelength has to be in nanometers  (1nm= 10⁻⁹ m) and that the energy we get is the energy per a single photon. Thus we will need to multiply this result by Avogadro's number to answer this question.

E = 3.1  x 10 ⁻¹⁹ J/ photon x 6.022 x 10 ²³photon/mol

E = 1.8 x 10⁵ J/mol

You might be interested in
Please answer this question ASAP
Nezavi [6.7K]

Answer:

put a test tube over the opening, remove it and quickly put a lit splint near the mout or in the tube. if you hear a squeaky pop it is hydrogen.

Explanation:

hydrogen ignites in air.

4 0
2 years ago
Determine how many ml of water you need to remove, by evaporation, if you have a 500 ml of 10.20 M HNO3 dilute solution and you
Ludmilka [50]

The total volume of water that would be removed will be 75 mL

<h3>Dilution equation</h3>

Using the dilution equation:

M1V1 = M2V2

In this case, M1 = 500 mL, V1 = 10.20 M, M2 = 12 M

Substitute:

V2 = 500 x 10.20/12

         = 425 mL

The final volume in order to arrive at 12 M HNO3 would be 425 mL from the initial 500 mL. Thus, the total amount of water that will be removed by evaporation can be calculated as:

500 - 425 = 75 mL

More on dilution can be found here: brainly.com/question/7208939

7 0
2 years ago
2. Which substance will form a solution with water? (Select all that app
cupoosta [38]

Answer:

sugar and salt, as they can dissolve in water. Sugar and salt have a high solubility in water. So, sugar and salt can form a solution with water.

Explanation:

7 0
2 years ago
How many moles are in 1.29 x 1024 hydrogen atoms in HF
zepelin [54]

Answer:

No. Moles  = 2.142   mole

7 0
2 years ago
Explain why 1 mole of diethyl ether requires less heat to
gizmo_the_mogwai [7]

The quantity of heat required to vapourize 1 mole of a substance depends on the kind of intermolecular forces between the molecules of the substance. Diethyl ether molecules are held together by weak dispersion forces compared to the stronger hydrogen bonding in ethanol. Therefore,  1 mole of diethyl ether requires less heat to  vapourize than is required to vapourize 1 mole of  ethanol.

Intermolecular forces hold the molecules a substance together in a given state of matter. The properties of a substance such as boiling point, melting point etc are dependent on the nature of intermolecular forces holding the molecules of the substance.

Diethyl ether molecules are held together by weak dispersion forces while molecules of ethanol are held together by hydrogen bonds.

Since hydrogen bonds are much stronger than dispersion forces, a greater quantity of heat is required to break the intermolecular hydrogen bonds in ethanol in order to vapourize them than is required to vapourize diethyl ether.

Therefore, owing to stronger intermolecular forces between molecules of ethanol, less heat is required to vapourize than is required to vapourize 1 mole of  ethanol.

Learn more: brainly.com/question/9328418

6 0
3 years ago
Other questions:
  • What is the chemical formula for Copper (II) nitrate?
    10·1 answer
  • The smalles part of an element that has all the properties of that element .
    6·2 answers
  • 1. Antarctica is a frozen land, so cold and icy that no trees can grow there. Yet scientists have discovered fossils(remains pre
    8·1 answer
  • Silver chloride is also known as <br>silver glance<br>silver copper glance<br>horn silver<br>all​
    6·1 answer
  • HELP ME!!!!
    7·1 answer
  • Ok, got it!!! thank you so much
    14·1 answer
  • The arrows show the changes of state.
    11·1 answer
  • Help meeeeeeeeeeeee its impossibleeeeee
    6·2 answers
  • B. from 52 moles of nitric acid, how many moles of silver nitrate will be produced?
    14·1 answer
  • What are the distinguishing features of each extraction process: pyrometallurgy, electrometallurgy, and hydrometallurgy? Explain
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!