number of atoms

[Dencology]

Approx. how many atoms of carbon are in 5.00*10(-7) grams of C3H8?

ans is 2.05*10(16)

how?

I am doing the following math:

5.00*10(-7) g C3H8 * 1mole C3H8/48g c3H8 * 3carbon/1mole C3H8 * 6.02*10(23)/1 Carbon atom= roughly 2.0*10(16)

anyone agree with me?

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[AndyK]

First, find how many moles of C3H8 there are:

(5.00*10^-7 g)/(44 g/mol) = ~ 1.1x10^-8 mol C3H8

Then, use Avogadro's number to find how many molecules there are:

(1.1x10^-8 mol C3H8) * (6x10^23 molecules C3H8/mol) = ~6.6x10^15 molecules of C3H8

For every molecule of C3H8, there are 3 carbon atoms, so just multiply 6.6x10^15 by 3 and you get approximately 2x10^16

 

[Zerconia2921]

First, find how many moles of C3H8 there are:

(5.00*10^-7 g)/(44 g/mol) = ~ 1.1x10^-8 mol C3H8

Then, use Avogadro's number to find how many molecules there are:

(1.1x10^-8 mol C3H8) * (6x10^23 molecules C3H8/mol) = ~6.6x10^15 molecules of C3H8

For every molecule of C3H8, there are 3 carbon atoms, so just multiply 6.6x10^15 by 3 and you get approximately 2x10^16

5x10e-7 x 1mole c3h8/44g c3h8 x 3moles c/1mole c3h8 x 6.02x10e23 = answer