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The fuel used in many disposable lighters is liquid butane, C4H10. Butane has a molecular weight of 58.1 grams in one mole. How many carbon atoms are in 2.50 g of butane?

User Joe Maher
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2 Answers

4 votes

Answer:

Do you have 1,04 ×10²³ carbon atoms in 2,50g of butane.

Step-by-step explanation:

  • With molecular weight you can know how many moles do you have from a quantity of grams:

2,50 g ₓ ( 1 mol butane / 58,1 g ) = 0,043 moles of butane

  • With moles and Avogadro number you can obtain the number of molecules, in this case, of butane:

0,043 moles of butane × ( 6,022×10²³ molecules / 1 mol ) =

2,59 ×10²² molecules of butane

  • Knowing a molecule of butane has four carbon atoms ( molecular formula of butane is C₄H₁₀) you can obtain the number of carbon atoms:

2,59 ₓ 10 ²² molecules of butane ( 4 carbon atoms / 1 molecule of butane ) =

1,04 ×10²³ carbon atoms

I hope it helps!

User Sylter
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4 votes
The first thing you need to do is calculate the molar mass of C4H10. To do this, look at a periodic table for the atomic mass of carbon and hydrogen. For Hydrogen it's 1.008 amu. For Carbon its 12.01 amu. This means that a mole of hydrogen has a mass of 1.008 amu. So to calculate the molar mass of C4H10:

atomic mass of H * number of H atoms in one molecule + atomic mass of C * number of C atoms in one molecule
1.008 * 10 + 4 * 12.01
= 58.12 g

So one mole of C4H10 would have a mass of 58.12 g.

Now you were told to find the number of moles for 2.50 g, so you need to change 2.50g into moles

2.50g *1 mole/ 58.12 g = .043014 moles of C4H10

You know that for every mole of C4H10, there are 4 moles of Carbon

so
.043014 mole C4H10 * 4 mole C/1 mole C4H10 = .172 mol C
Now to find the number of atoms, use avogadros numbe5r

6.022 * 10^23 * .17 mol = 1.024 × 10^23 atoms your answer.The first thing you need to do is calculate the molar mass of C4H10. To do this, look at a periodic table for the atomic mass of carbon and hydrogen. For Hydrogen it's 1.008 amu. For Carbon its 12.01 amu. This means that a mole of hydrogen has a mass of 1.008 amu. So to calculate the molar mass of C4H10:

atomic mass of H * number of H atoms in one molecule + atomic mass of C * number of C atoms in one molecule
1.008 * 10 + 4 * 12.01
= 58.12 g

So one mole of C4H10 would have a mass of 58.12 g.

Now you were told to find the number of moles for 2.50 g, so you need to change 2.50g into moles

2.50g *1 mole/ 58.12 g = .043014 moles of C4H10

You know that for every mole of C4H10, there are 4 moles of Carbon

so
.043014 mole C4H10 * 4 mole C/1 mole C4H10 = .172 mol C
Now to find the number of atoms, use avogadros numbe5r

6.022 * 10^23 * .17 mol = 1.024 × 10^23 atoms your answer.

Hope it helps
User Cao Dongping
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