Calculating Moles of Substances in 88g of Carbon Dioxide

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In summary, the conversation discussed finding the number of moles of each substance in 88g of carbon dioxide. Using the molar mass of CO2, it was determined that there are 2 moles of CO2, 2 moles of carbon, and 4 moles of oxygen in 88g of CO2. The conversation also mentioned calculating the percent by mass of carbon and oxygen in CO2.
  • #1
nobahar
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Hello!
How many moles of each substance are contained in 88g of carbon dioxide?
Since it's CO2:
Ar of carbon= 12
Ar of oxgen = 16
Mr of Carbon dioxide = 44
88g/44= 2 Mol of CO2 formula units
Since the ratio is 1:2 carbon to oxygen:
(88/3)/12=22/9 Mol of Carbon
(i.e. 1/3 of 88g is how many grams carbon represents?)
and
(176/3)/16=11/3 Mol of oxygen
(i.e. 2/3 of 88g is how many grams oxygen represents)
Is this right? Any replies much appreciated! Thanks in advance!
Jay
 
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  • #2
Ar of carbon= 12
Ar of oxgen = 16
Mr of Carbon dioxide = 44
88g/44= 2 Mol of CO2 formula units
Since the ratio is 1:2 carbon to oxygen:

This part is good, but afterward I'm not quite sure how your calculations go. Here's a simpler way, I believe:

You have 2mol of CO2. This means you have 2mol C and 4mol O (each atom is multiplied by the mole amount (2).)
2mol C = 2mol(12g/mol) = 24g
4mol O = 4mol(16g/mol) = 64g
Make sure all masses add up to the total mass (88g), and that's it! It gets a bit more complicated for larger molecules (e.g. H3PO4) or with messier numbers (8.57mol rather than 2mol) but they should work the same way.

So this is the mass of each; if you wanted percent by mass (common for high school or basic college chem):
C = 24g/88g x 100 = ~27%
O = 64g/88g x 100 = ~73%
 
Last edited:
  • #3
I don't know where they were going either.
Thanks for the help though!
 

1. What is molar mass?

Molar mass is the mass of one mole of a substance, which is equal to its atomic or molecular weight in grams. It is measured in units of grams per mole (g/mol) and is used to convert between the mass of a substance and the number of moles present.

2. How is molar mass calculated?

Molar mass is calculated by adding the atomic mass of each element in a molecule, as listed on the periodic table, and multiplying by the number of atoms of that element present. For example, the molar mass of water (H2O) would be calculated as (2 x 1.008 g/mol for hydrogen) + (1 x 15.999 g/mol for oxygen) = 18.015 g/mol.

3. Why is molar mass important?

Molar mass is important because it is used to convert between the mass of a substance and the number of moles present. This is necessary for many chemical calculations, such as determining the amount of reactants needed in a reaction or the yield of a reaction.

4. Is molar mass the same as molecular weight?

Yes, molar mass and molecular weight are essentially the same concept. They both refer to the mass of one mole of a substance, but molar mass is typically used for elements and compounds, while molecular weight is used for molecules and compounds. The values may differ slightly due to the use of different units, but they are often used interchangeably.

5. How does molar mass relate to Avogadro's number?

Avogadro's number (6.022 x 10^23) is the number of particles in one mole of a substance. This number is used to convert between the number of particles and the number of moles. For example, if the molar mass of a substance is 18 g/mol, then one mole of that substance would contain 6.022 x 10^23 molecules.

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