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ololo11 [35]
3 years ago
13

Thousands of years people believe the stars move across our sky explain why we now has a different explanation of why stars move

across the night sky? Be sure to mention reference.
Chemistry
1 answer:
vladimir1956 [14]3 years ago
3 0
They do not move they stay in the same same place it may look like they move because of the earth rotation
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Select three parts of a simple electrolytic cell and explain their functions in the space below.
kotegsom [21]
A cathode is the location in an electrolytic cell where reduction reactions take place.

An anode is the location in an electrolytic cell where oxidation reactions occur.

An electrolyte solution is any substance containing free ions that make the substance electrically conductive.

<span>An external electrical energy source like a  battery or a transformer is used to drive the non-spontaneous reaction.</span>
8 0
3 years ago
Competition occurs when
Katen [24]

Answer:

Competition occurs when <em>(A) two or more organisms need the same resource.</em>

Explanation:

I dont think it could be (B), (C) or (D) because those don't really make sense.

3 0
2 years ago
A hypothetical element, E, has two stable isotopes. One isotope has a natural abundance of 68.037% and has an atomic mass of 46.
I am Lyosha [343]
  • If the abundance of the first isotope is 68.037%, then the abundance of the second isotope is 100%-68.037%.

Substituting into the atomic mass formula,

47.574=(46.449)(0.68037)+x(1-0.68037)\\\\ 47.574=31.60250613+0.31963x\\\\15.97149387=0.31963x\\\\x \approx \boxed{49.969 \text{ u}}

6 0
2 years ago
Which isotope has the greatest number of protons?
tino4ka555 [31]

Answer:

The isotope with the greatest number of protons is:

  • <u>option D:  Pu-239, with 94 protons</u>

Explanation:

The number of <em>protons</em> is the atomic number and is a unique number for each type of element.

You can tell the number of protons searching the element in a periodic table and reading its atomic number.

Thus, this is how you tell the number of protons or each isotope

Sample       Chemical symbol  Element       atomic number   # of protons

A Pa-238       Pa                         protactinium         91                        91

B U-240         U                          uranium                 92                       92

C Np-238       Np                        neptunium            93                       93

D Pu-239        Pu                        plutonium              94                       94

8 0
3 years ago
Who is considered the founder of the periodic table of the elements?
nata0808 [166]

Answer:

Dmitry Mendeleev

Explanation:

Around 1869 a Russian scientist, Dmitry Mendeleev formed what is now known as the periodic table or chart. The Mendeleevian periodic table was based on the atomic weights of elements using the periodic law. The periodic law states that "chemical properties of elements are a periodic function of their atomic weights".

The modern periodic table was re-stated by Henry Moseley in the 1900s. He changed the basis of the periodic law to atomic masses.

7 0
3 years ago
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