Molecular formula of combustion?

[raoulduke1]

complete combustion of 1.1g of a compound of C,H and O gives 2.2g of CO2 and 0.9g of H2O.
The compound has a relative molar mass close to 130.
Find the molecular formula and true molar mass?

dont even no where to begin

 

[Borek]

Google "finding empirical formula".

 

[stonecoldgen]

so you got the masses of the products right? 2.2g for CO2 and 0.9g for H2O.

you knowthe molar masses of those elements by looking at the periodic table

for example, the moalr mass of CO2 is (approximately because of rounding)= 12+16+16=44g/moldo the same thing to get the molar mass of H2O (hydrogen is 1) to get the H2O moles

what has me confused though is that it doesn't appear to obbey the conservation of mass law, how can you have 1.1g of something and get 2.2g+0.9g of something else?maybe I am just reading wrong...

then divide the mass of the substances by the molar massses, to get number of moles, so 2.2/44=0.05 moles of CO2

 

[Borek]

what has me confused though is that it doesn't appear to obbey the conservation of mass law, how can you have 1.1g of something and get 2.2g+0.9g of something else?


maybe I am just reading wrong...

Combustion means there is a source of oxygen.

Please pay attention to what and how you write, don't ignore capital letters and watch for typos.

 

[DeeNos]

I would first start by calculating the molar masses of CO2 and H2O using the atomic masses of carbon, hydrogen, and oxygen. From the given information, we know that 1.1g of the compound produced 2.2g of CO2 and 0.9g of H2O. Using the molar masses of CO2 (44.01 g/mol) and H2O (18.02 g/mol), we can calculate the moles of each compound produced.

2.2 g CO2 x (1 mol CO2 / 44.01 g CO2) = 0.05 mol CO2
0.9 g H2O x (1 mol H2O / 18.02 g H2O) = 0.05 mol H2O

Since the ratio of moles of CO2 and H2O is 1:1, we can infer that the number of moles of carbon and hydrogen in the compound must also be in a 1:1 ratio. This means that the molecular formula of the compound is likely C1H1, which simplifies to CH.

To find the true molar mass, we can use the given information that the relative molar mass is close to 130. This means that the actual molar mass is likely slightly higher than 130 g/mol. Since the molecular formula is CH, the molar mass would be the sum of the atomic masses of carbon (12.01 g/mol) and hydrogen (1.01 g/mol), which is 13.02 g/mol. This is significantly lower than 130 g/mol, so it is possible that the compound has a higher molecular formula, such as C6H6, which would have a molar mass of 78.11 g/mol.

In conclusion, based on the given information, the molecular formula of the compound is likely CH, and the true molar mass is possibly higher than 130 g/mol, potentially closer to 78.11 g/mol. Further analysis and experimentation may be needed to determine the exact molecular formula and molar mass of the compound.