Chem AO2 questions

hydrocarbon was completely combusted in excess oxygen.

In the experiment:

• 88.0 g of carbon dioxide gas was produced

• 54.0 g of water was produced

The molar mass of the hydrocarbon was later found to be 58 g mol⁻¹.

a.

Calculate the amount, in moles, of carbon and hydrogen produced in this experiment.

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b.

Using this information, determine the empirical formula of the hydrocarbon.

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c.

Determine the molecular formula of the hydrocarbon.

Useful molar masses?

Application

There are many different methods of determining the empirical formula of a compound. To

determine the empirical formula of a hydrocarbon, a combustion reaction can be used.

In one experiment, 100 g of an unidentified hydrocarbon was combusted in excess oxygen,

and 306.9 g of Carbon Dioxide gas and 146.7g of water were produced.

a. Calculate the amount, in moles, of Carbon and Hydrogen produced in this experiment

(3 Marks)

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b. Using this information, calculate the empirical formula of the hydrocarbon combusted

in this experiment (2 Marks)

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c. If the molecular mass of this compound is found to be (86 g/mol), identify the

molecular formula of the organic compound. (1 Mark)

a

a

a

a