I need to know if these two statements are always true, AT; sometimes true, ST; or never true, NT. Thanks!
10. A mole of carbon atoms has a mass approximately three times as great as the mass of a mole of helium atoms.
11. The gram molecular mass of nitrogen is 14.0g.
I don't know how to answer but I'll give you information and let you choose.
10. A mole of carbon atoms has a mass of 12.011 grams and a mole of He atoms has a mass of 4.002602 grams. In my book, 12.011 is approximately 3 x 4.002602 but it all depends upon how approximate you are being. You be the judge.
11. Nitrogen occurs in the free state as N2, not as N; therefore, the gram atomic mass is 14.0 and the gram molecular mass is 14.0 x 2 = 28.0 grams.
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To determine whether these statements are always true (AT), sometimes true (ST), or never true (NT), let's analyze each statement individually:
10. A mole of carbon atoms has a mass approximately three times as great as the mass of a mole of helium atoms.
To evaluate this statement, we need to compare the atomic masses of carbon and helium. The atomic mass of carbon is approximately 12.01 grams per mole (g/mol), while the atomic mass of helium is approximately 4.00 g/mol.
So, the statement implies that the mass of a mole of carbon atoms (12.01 g/mol) is approximately three times the mass of a mole of helium atoms (4.00 g/mol).
We can calculate the relative mass ratio:
Mass ratio = (Mass of carbon atoms) / (Mass of helium atoms)
= 12.01 g/mol / 4.00 g/mol
= 3.0025
Therefore, the mass ratio is approximately equal to 3.0025. This means that a mole of carbon atoms has a mass that is roughly three times the mass of a mole of helium atoms.
Conclusion: The statement is AT (always true).
11. The gram molecular mass of nitrogen is 14.0g.
The atomic mass of nitrogen is approximately 14.01 g/mol. Hence, the statement implies that the gram molecular mass of nitrogen is exactly 14.0 grams.
To confirm whether this statement is true, we calculate the gram molecular mass of nitrogen:
Gram molecular mass of nitrogen = Atomic mass of nitrogen (g/mol)
Therefore, the gram molecular mass of nitrogen is approximately 14.01 g/mol, not exactly 14.0 g.
Conclusion: The statement is NT (never true).
In summary:
10. A mole of carbon atoms has a mass approximately three times as great as the mass of a mole of helium atoms. - AT (always true)
11. The gram molecular mass of nitrogen is 14.0g. - NT (never true)