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
Advocard [28]
2 years ago
6

Its due this monday

Chemistry
1 answer:
Ira Lisetskai [31]2 years ago
3 0

Answer:

13. Index Fossils

14. Index Fossils

15. C

16. Geologists use index fossils to define geological periods.

17. C

18. A

You might be interested in
Solid strontium chromate, SrCrO4, dissolves into its respective ions at 25°C. Suppose that in a particular solution,
user100 [1]

Answer:

I think it's d but I'm not positive

5 0
2 years ago
Read 2 more answers
Using the Bohr model, determine the energy in joules of the photon produced when an electron in a Li2+ ion moves from the orbit
djverab [1.8K]

Answer:

1.64x10⁻¹⁸ J

Explanation:

By the Bohr model, the electrons surround the nucleus of the atom in shells or levels of energy. Each one has it's energy, and the electron doesn't fall to the nucleus because it can reach another level of energy, and then return to its level.

When the electrons go to another level, it absorbs energy, and then, when return, this energy is released, as a photon (generally as luminous energy). The value of the energy can be calculated by:

E = hc/λ

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

The wavelength can be calculated by:

1/λ = R*(1/nf² - 1/ni²)

Where R is the Rydberg constant (1.097x10⁷ m⁻¹), nf is the final orbit, and ni the initial orbit. So:

1/λ = 1.097x10⁷ *(1/1² - 1/2²)

1/λ = 8.227x10⁶

λ = 1.215x10⁻⁷ m

So, the energy is:

E = (6.626x10⁻³⁴ * 3.00x10⁸)/(1.215x10⁻⁷)

E = 1.64x10⁻¹⁸ J

3 0
3 years ago
Suggest why it might be difficult and dangerous to test sodium for electrical conductivity?​
lukranit [14]

Answer:

It might cause fire or extreme smoke.

Explanation:

8 0
2 years ago
The atomic theory proposed by dalton has been
Sidana [21]

What did Dalton's atomic theory contribute to science?

Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.

3 0
3 years ago
a solid with a low melting point is most likely what? A.ionic B. covalent C. metallic or D. None of the above.
ziro4ka [17]
The correct answer of the given question above would be option D. None of the above. When a solid has a low melting point, it is most likely a simple molecular substance. When it is ionic, covalent or metallic, it is already considered as a solid with a high melting point. 
3 0
3 years ago
Other questions:
  • This form of matter does not have definite shape and is not easily compressed.
    13·1 answer
  • Which one of the following substances would be the most soluble in CCl4?
    15·1 answer
  • What were the names of the minerals and types of rocks?
    9·2 answers
  • 5. Common (most stable) mass numbers of the following elements are Al-27, Pt-195, Co-59,
    8·1 answer
  • 6. As you go down a family or group on the periodic table *
    14·1 answer
  • How much more basic is a solution with pH 10 than a solution with pH 8?
    12·2 answers
  • Scoring Scheme: 3-3-2-1 Part II. You considered the properties of two acid-base indicators, phenolphthalein and methyl orange. M
    7·1 answer
  • an object displaces 32 mL of water and a known density of 0.0625 g/mL. What is the mass of the object?
    8·2 answers
  • If 9 moles of P203 are formed, how many<br> moles of O2 reacted?
    9·1 answer
  • The H⁺ concentration in an aqueous solution at 25 °C is 9.1 × 10⁻⁴. What is [OH⁻]?
    9·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!