We’re being asked to determine the empirical formula of a compound composed of C, H, and O given the combustion analysis.
Recall that in combustion analysis, a compound reacts with excess O2 to form products.
For a compound composed of C, H, and O, the reaction looks like this:
CxHyOz + O2 (excess) → x CO2 + y H2O
This means we need to do the following steps:
Step 1: Calculate the mass of C and H in the compound.
Step 2: Calculate the mass of O in the compound.
Step 3: Determine the lowest whole number ratio of C, H, and O to get the empirical formula.
Step 4: Get the ratio of the molar mass and empirical mass to determine the molecular formula.
a) Tartaric acid is composed of carbon, hydrogen and oxygen. A sample weighing 0.400g is subjected to combustion analysis and produced 0.469g carbon dioxide and 0.144g water. Find the empirical formula of tartaric acid.
b) The molar mass of tartaric acid is 150g/mol. Calculate its molecular formula
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What scientific concept do you need to know in order to solve this problem?
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