For example, the atomic mass of an oxygen atom is 16.00 amu; that means the molar mass of an oxygen atom is 16.00 g/mol. Further, if you have 16.00 grams of oxygen atoms, you know from the definition of a mole that your sample contains 6.022 x 10^23 oxygen atoms.
Answer:
16 is the mass number. 8 is the atomic number.
Answer:
The mass was there all along, it was just in the air. The weight of the oxygen from the air is not weighed in the beginning, only at the end as part of the product, making it seem like there is a total mass change.
Answer:
Ionic bonds hold charged particles in solid NaCl together, such that they are unable to move or conduct electricity.
Explanation:
Consider an electric current that flows through a conductor: charge moves in a uniform direction from one end of the conductor towards the other.
Thus, there are two conditions for a substance to conduct electricity:
- The substance shall contain charged particles, and
- These charged particles shall be free to move across the substance.
A conductor of electricity shall meet both requirements.
Now, consider the structure of solid NaCl
. NaCl is an ionic compound. It contains an ocean of oppositely charged ions:
- Positive
ions, and - Negative
ions.
Ions carry charge. Thus, solid NaCl contains charged particles and satisfies the first condition.
Inside solid NaCl
, electrostatic attractions ("ionic bonds") between the oppositely charged ions hold these ions in rigid ionic lattices. These ions are unable to move relative to each other. As a result, they cannot flow through the solid to conduct electricity. Under solid state, NaCl is unable to satisfy the second condition.
As a side note, melting NaCl into a liquid breaks the ionic bonds and free the ions from the lattice. Liquid NaCl is a conductor of electricity.