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Aballoon contains 6.0 moles of helium. A hole in the balloon lets 4.0 moles of helium escape the balloon. How many atoms of m remain in the balloon?

Answer 1

If I have 6 chocolates, and give 4 away, how many chocolates do I have left?

Now of course you wanted the number of atoms remaining in the balloon. But the use of a #"mole"# specifies that number.

One mole of stuff specifies #6.022xx10^23# individual items of that stuff. To make things easier I could write #6.022xx10^23=N_A " Avogadro's number"#, which is something that would be recognized by all chemists (including you!).

So, I am left with #2xxN_A# helium atoms (of course helium is a mono-atomic gas). You can do the arithmetic if you like. Can you tell me the mass of gas left in the balloon?

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Answer 2

Ellie Andrews

After 4.0 moles of helium escape the balloon, there are 2.0 moles of helium remaining. To find the number of atoms remaining, multiply the number of moles by Avogadro's number (6.022 × 10^23 atoms/mol):

2.0 moles * 6.022 × 10^23 atoms/mol = 1.2044 × 10^24 atoms

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.