Answer:
C. Both observation 1 and observation 2.
Explanation:
The heliocentric model states that the Earth and planets revolve around the Sun at the center of the Solar System.
Observation 1 was answered by Nicolas Copernicus, father of the heliocentrism, in 1543. The reverse effect is an illusion created because the Earth revolves faster around the Sun than Mars.
And observation 2 also is explained by the model because the rotation of the earth made that the Stars be closer to it at different times of the year.
I hope this answer helps you.
Answer:
Using dimensional analysis, we have....
4.515x1024 atoms x 1 mole/6.022x1023 atoms = 7.4975 moles = 7.498 moles of PD
So the official answer is 7.5
Explanation:
"Purellium Distinkamide" is a silly joke name for a made-up compound. The idea of this question is that no matter what the substance we are talking about is - water (H2O), hydrogen gas (H2), or even "Purellium Distinkamide" - a mole is always the same number of molecules, 6.022 x 1023. This is Avogadro's number and you have probably seen it around class a lot!
11. because |14-25|=11 hope this helps.
<u>Answer:</u> Group 1 ions are known as cations and Group 17 ions are known as anions.
<u>Explanation:</u>
Ions are formed when an atom looses or gains electrons.
If an atom gains electrons, it leads to the formation of negative ions known as anions. <u>For Example:</u> Fluorine is a Group 17 element which gains 1 electron to form ions.
If an atom looses electrons, it leads to the formation of positive ions known as cations. <u>For Example:</u> Sodium is a Group 1 element which looses 1 electron to form ions.
Hence, group 1 ions are known as cations and Group 17 ions are known as anions.