how many atoms of carbon are there in 16.38 lbs of C3H7COOH?

Question

i dont know what im doing:(

Answer 1

take the molar wieght of C3H7COOH
should be around 88 ish
find the number of moles you have in 16.38 lbs.
multiply that by Avogadro's number 6.023 x10^23
multiply that by 4 to get the number of carbon atoms

so its mass -> moles -> molecules -> atoms

Answer 2

You might need a roadmap of sorts.

Conversion factors are always fractions (like g/mol). Most of these problems are multiplication or division -- just do the operation that cancels units. This is sort of like playing dominos, except instead of matching tiles end to end, you match them diagonally.

You need to know:

propanol = C3H7COOH (you don't really need to know this, it just is easier to type)

1 molec propanol = 4 atoms C or
(4 atoms C)/(1 mol of propanol)
(from chemical formula)

6.02 e 23 (10^23) molec = 1 mol or
(6.02e23 atoms of propanol)/(1 mol of propanol)
(from Avogadro's number)

1.00 mol propanol = 88.0 g of propanol or
(88.0 g of propanol)/(1 mol of propanol)
(from adding up the atomic weights in the Periodic Table)

1000 g = 1 kg or
(1000 g of propanol)/(1 kg of propanol) (metric conversions)

2.2 lbs = 1 kg or
(2.2 lbs of propanol)/(1 kg of propanol) (metric conversions)

Starting with 16.38 lbs (think of it as a tile with lbs on top), you need to find the factor (or tile) with lbs in the denominator (bottom), keeping in mind that each fraction above can be flipped (as long as you keep the unit) since the top and bottom are equivalent (minor digression - that's the definition of "1" in algebra - denominator = numerator and multiplying by 1 doesn't change the value of a quantity).

Hopefully, you see that multiplying by (1 kg of propanol)/(2.2 lbs of propanol) will cancel out the lbs. and you have now calculated the number of kgs of carbon.

You should get an answer between 1e26 and 1e27.