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
pentagon [3]
3 years ago
11

Celestial object A is composed of 92.1 percent hydrogen and 7.8 percent helium while celestial object B is made up of ice, froze

n carbon dioxide, rock, and dust. What is celestial object A? A. asteroid B. comet C. dwarf planet D. black hole E. star
Chemistry
1 answer:
Andrew [12]3 years ago
5 0

Answer:

star

Explanation:

stars are composed of 92.1 percent hydrogen and 7.8 percent helium.

You might be interested in
Which of the following statements is not correct?
Ahat [919]
A is incorrect as some ionic compounds can be stronger than covalent compounds.
8 0
4 years ago
What ions are in water all the time?
Oksana_A [137]

Answer:

(Ca2 +, Mg2 +, Na+, and K+) and four major anions ( , , SO 4 2 - , and Cl-) with ionic forms of N, P, Fe, and other trace elements at lower concentrations (Livingstone 1963, Meybeck 1979) (Table 4.7).

6 0
3 years ago
A double replacement reaction can be best described as a reaction in which
ExtremeBDS [4]
<h3>Answer </h3>

Option C= ions are exchanged between two compounds.

<h3>Explanation </h3>

A double displacement reaction, also known as a double replacement reaction or metathesis, is a type of chemical reaction where two compounds react, and the positive ions (cation) and the negative ions (anion) of the two reactants switch places, forming two new compounds or products. For example,

                                    Na2S + 2HCl → H2S + 2NaCl

Option D is incorrect because electrons are exchanged between the atoms in oxidation –reduction reactions.


3 0
3 years ago
WILL GIVE POINTS AND BRAINLIEST<br> Question:<br> Number of H− ions in 5.22 g of SrH2
Sophie [7]

Answer:

moles H = 2 x 0.0649=0.130

ions = 0.130 x 6.02 x 10^23=7.81 x 10^22

Explanation:

4 0
3 years ago
The electron in a hydrogen atom, originally in level n = 8, undergoes a transition to a lower level by emitting a photon of wave
timofeeve [1]

Explanation:

It is given that,

The electron in a hydrogen atom, originally in level n = 8, undergoes a transition to a lower level by emitting a photon of wavelength 3745 nm. It means that,

n_i=8

\lambda=3745\ nm

The amount of energy change during the transition is given by :

\Delta E=R_H[\dfrac{1}{n_f^2}-\dfrac{1}{n_i^2}]

And

\dfrac{hc}{\lambda}=R_H[\dfrac{1}{n_f^2}-\dfrac{1}{n_i^2}]

Plugging all the values we get :

\dfrac{6.63\times 10^{-34}\times 3\times 10^8}{3745\times 10^{-9}}=2.179\times 10^{-18}[\dfrac{1}{n_f^2}-\dfrac{1}{8^2}]\\\\\dfrac{5.31\times 10^{-20}}{2.179\times 10^{-18}}=[\dfrac{1}{n_f^2}-\dfrac{1}{8^2}]\\\\0.0243=[\dfrac{1}{n_f^2}-\dfrac{1}{64}]\\\\0.0243+\dfrac{1}{64}=\dfrac{1}{n_f^2}\\\\0.039925=\dfrac{1}{n_f^2}\\\\n_f^2=25\\\\n_f=5

So, the final level of the electron is 5.

4 0
3 years ago
Other questions:
  • What are the important chemical reactions in the food industry
    5·1 answer
  • An object has a mass of 4.9g and a volume of 14.ml.what is the density of the object?
    8·1 answer
  • How many times faster will oxygen gas diffuse than carbon dioxide
    10·1 answer
  • Which atomic model was proposed as a result of J. J. Thomson’s work?
    13·2 answers
  • Which of the following is made up of only one type of atom? 1) NO 2) He 3)CO 4)MgS
    8·1 answer
  • Help!! Thank you so much ❤️
    11·1 answer
  • Mass is 112.8g and the volume is 63cm3 , whats the density of the cube?
    6·1 answer
  • 6th grade science I mark as brainliest zoom in if needed
    10·1 answer
  • What are the properety of covalent bond​
    15·2 answers
  • PLEASE HELP CHEMISTRY WORK number 15
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!