Problem: Determine the empirical and molecular formulas of each of the following substances.Caffeine, a stimulant found in coffee, contains 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass and has a molar mass of 195 g/mol.

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Step 1: 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass. Recall that mass percent is given by:


% mass=mass of Xtotal mass×100


Assuming we have 100 g of the compound, this means we have 49.5 g C, 5.15 g H, 28.9 g N, and 16.5 g O.

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Problem Details

Determine the empirical and molecular formulas of each of the following substances.

Caffeine, a stimulant found in coffee, contains 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass and has a molar mass of 195 g/mol.

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