Math Problem Statement

A compound contains only carbon, hydrogen, nitrogen, and oxygen. Combustion of a 2.18 g sample burns in excess oxygen yields 3.94 g of CO2 and 1.89 g of H20. A separate experiment shows that a 1.23 g sample contains 0.235 g of N. Calculate the moles of C in the sample.

Solution

To find the moles of carbon in the sample, we can follow the steps outlined below:

Step 1: Find the moles of carbon in the sample.

When the compound combusts, all of the carbon present converts to CO₂. We can use the mass of CO₂ produced to calculate the amount of carbon in the sample.

Given:

  • Mass of CO₂ = 3.94 g
  • Molar mass of CO₂ = 44.01 g/mol
  • Molar mass of carbon (C) = 12.01 g/mol

First, we calculate the moles of CO₂ produced:

Moles of CO2=3.94g44.01g/mol=0.08957mol of CO2\text{Moles of CO}_2 = \frac{3.94 \, \text{g}}{44.01 \, \text{g/mol}} = 0.08957 \, \text{mol of CO}_2

Each mole of CO₂ contains one mole of carbon atoms, so:

Moles of C=0.08957mol\text{Moles of C} = 0.08957 \, \text{mol}

Thus, the sample contains 0.08957 moles of carbon.

Summary:

  • Moles of carbon in the sample = 0.08957 mol

Would you like to see the next steps or explanations for further analysis, such as the determination of hydrogen and nitrogen?

Here are some related questions to consider:

  1. How do you determine the amount of hydrogen in the sample?
  2. How can the empirical formula of the compound be calculated?
  3. What is the significance of the excess oxygen in combustion analysis?
  4. How do you calculate the molecular formula based on the empirical formula and molar mass?
  5. How do the elements nitrogen and oxygen factor into combustion analysis?

Tip: Always check the stoichiometry of the products to ensure the relationship between the elements and the compound formula is clear.

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Math Problem Analysis

Mathematical Concepts

Stoichiometry
Combustion Analysis
Mole Calculations

Formulas

Moles = Mass / Molar Mass
Moles of CO2 = Mass of CO2 / Molar Mass of CO2
Moles of Carbon = Moles of CO2 (since each CO2 molecule contains one carbon atom)

Theorems

Law of Conservation of Mass

Suitable Grade Level

Grades 10-12