Answer:
Density is a measure of mass per unit of volume. Density is a measure of mass per volume. The average density of an object equals its total mass divided by its total volume.
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Answer:the CO2 molecule has an excess of electron
Answer:
A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.
Explanation:
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In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:

As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.
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Answer: Option (3) is the correct answer.
Explanation:
Atomic number of lithium is 3 and its electronic distribution is 2, 1. So, to attain stability it will loose an electron and hence, it forms a single bond.
Atomic number of chlorine is 17 and it has 7 valence electrons. Hence, in order to attain stability it will gain one electron and therefore, it forms a single bond only.
Atomic number of nitrogen is 7 and its electronic distribution is 2, 5. Therefore, to attain stability it needs to gain 3 more electrons. Hence, a nitrogen atom is able to form a triple bond and also it is able to form a double bond.
Hydrogen has atomic number 1 and it attains stability by gaining one electron. Therefore, a hydrogen atoms always forms a single bond.
Atomic number of fluorine is 9 and its electronic distribution is 2, 7. To complete its octet it needs to gain one electron. Hence, a fluorine atom always forms a single bond.
Thus, we can conclude that out of the given options nitrogen is most likely to form multiple (double or triple) bonds.
Answer:
the atomic number is 5
the atomic mass is 11
Explanation:
The atomic number is the amount of protons inside the nucleus, and this number also equals the amount of electrons. Since it shows you the nucleus and the electrons, all you need to do is count the protons (positive charge inside the nucleus) or count all the electrons (negative charge outside the nucleus, in the rings) and you should have your atomic number.
As for mass, all you need to do is count all the protons and neutrons inside the nucleus and add them up. Protons = 5, Neutrons = 6. (you add them since the equation for atomic mass is Atomic Mass = Protons + neutrons. This works every time)
5+6= 11, so your atomic mass is 11
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