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Eduardwww [97]
3 years ago
15

How can scientists know what happened millions of years ago if no one was there to see it?​

Chemistry
1 answer:
xxMikexx [17]3 years ago
4 0

Answer:

In the 150 years since Darwin proposed the theory of evolution by natural selection, a mountain of evidence has accumulated ... How can you know what happened millions of years ago if no one was there to see it? Evidence and observation are the building blocks of all scientific inquiry; evolutionary science is no different

Explanation:

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Which is one way that Dalton's atomic theory has been shown to be incorrect?
KATRIN_1 [288]
The answer is D. His belief is was that atoms could not be split. That is what was disproved really fast ;)
6 0
3 years ago
Magnesium chloride is a salt formed with ionic bonds between one magnesium ion and two chloride ions. Magnesium has two electron
katrin [286]

Answer:

The magnesium atom loses 2 electron to the 2 atoms of chlorine. The 7 valency electrons of each chlorine atom will now be 8 to attain stable configuration. The final compound is written as MgCl2.

Explanation:

Ionic compounds are compound formed from the transfer of electron(s). One atom of the element loses electron(s) while the other atom gains electron(s).

The compound Magnesium chloride is an ionic compound . The bond between an atom of magnesium and 2 atoms of chlorine is an ionic bonding.

The valency electron of magnesium is 2 electron , for the atom of magnesium to  attain octet rule, it will easily lose it 2 electrons to the chlorine atoms.

The chlorine atom on the other hand has 7 valency electrons, to attain octet configuration it will most likely gain 1 electron to become stable.

The magnesium atom loses 2 electron to the 2 atoms of chlorine. The 7 valency electrons of each chlorine atom will now be 8 to attain stable configuration. The final compound is written as MgCl2.

7 0
3 years ago
The rate of effusion of oxygen to an unknown gas is 0.935. what is the other gas?
Kamila [148]

Answer:

N2

Explanation:

Rate of effusion is defined by Graham's Law:  

(Rate 1/Rate 2) = (sqrt (M2)/ sqrt (M1))

(Where M is the molar mass of each substance. )

Molar Mass of oxygen, O2, is 32 (M1).

Rate of effusion of O2 to an unknown gas is .935(Rate 1).  

Rate 2 is unknown so put 1.

Solve for x (M2).

.935/1 = sqrt x/ sqrt32

.935 x sqrt 32 = sqrt x

5.29 = sq rt x

5.29^2 = 27.975 = 28  

N2 has a molar mass of 28 so it is the correct gas.

4 0
3 years ago
An extremely soluble salt is added to water, and all of it dissolves. Is it at equilibrium? Explain.
alexdok [17]
Once the substance stops dissolving, the system is at equlibrium with the water and the undissolved salt now, if it is in the process of dissolving because it is completely soluble but has not been able to completely dissolve, it is not at equilibrium
5 0
3 years ago
Fungi have eukaryotic cells (large cells with a nucleus), like animals and plants<br> True or false?
Serggg [28]
True your answer is true
8 0
3 years ago
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