Concept explainers
The combustion of 3.795 mg of liquid B, which contains only C, H, and O, with excess oxygen gave 9.708 mg of CO2 and 3.969 mg of H2O. In a molar mass determination, 0.205 g of B vaporized at 1.00 atm and 200.0°C and occupied a volume of 89.8 mL. Derive the empirical formula, molar mass, and molecular formula of B and draw three plausible structures.
Interpretation:
Empirical formula, molar mass and molecular formula of B have to be derived; three plausible structures have to be drawn.
Concept introduction:
Steps to calculate empirical formula:
- Convert the mass of elements into moles.
- Divide each mole value by the smallest number of moles calculated.
- Round to the nearest whole number.
Number of moles = Molarity
Explanation of Solution
Calculate moles of each given elements:
The mass of oxygen is found by difference:
Convert moles of carbon into mass in mg:
Convert moles of hydrogen into mass in mg:
This gives the formula
Now, let’s calculate moles using the ideal gas equation, and then calculate the molar mass.
The formula mass of
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Chapter 24 Solutions
Chemistry
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