CHN analysis calculator

CHN Analysis Calculator

Created by Team y2calculate.com
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What is CHN Analysis?

CHN analysis, also known as elemental analysis, is a laboratory technique used to determine the composition of a sample in terms of the elements carbon (C), hydrogen (H), and nitrogen (N). This method involves the combustion of the sample, resulting in the formation of CO₂, H₂O, and N₂, which are then quantified to determine the percentages of carbon, hydrogen, and nitrogen in the sample. This technique is widely used in chemistry, biochemistry, environmental science, and various industrial applications to assess the chemical makeup of organic and inorganic substances.

Purpose of CHN Analysis Calculator

The purpose of a CHN analysis calculator is to simplify the process of converting the percentage composition of carbon, hydrogen, and nitrogen into their corresponding mole ratios, which can then be used to determine the empirical formula of the compound. This tool is particularly useful for students, researchers, and professionals who need to quickly and accurately determine the simplest ratio of elements in a compound based on its elemental analysis data. By inputting the mass percentages of each element, the calculator provides the empirical formula, which represents the simplest whole-number ratio of atoms in the compound.

Formula for Calculating Empirical Formula

The empirical formula of a compound is the simplest whole-number ratio of the elements present in the compound. To calculate the empirical formula using CHN analysis, follow these steps:

  1. Convert Percentages to Grams: Assume you have 100 grams of the sample, so the percentage of each element directly translates to grams. For example, if a compound is 40% carbon, 6.7% hydrogen, and 53.3% nitrogen, you have 40 grams of carbon, 6.7 grams of hydrogen, and 53.3 grams of nitrogen.
  2. Convert Grams to Moles: Use the atomic masses of the elements to convert the grams to moles.

    Moles of element = mass of element (g) / atomic mass of element (g/mol)

    • Carbon: Atomic mass = 12.01 g/mol
    • Hydrogen: Atomic mass = 1.008 g/mol
    • Nitrogen: Atomic mass = 14.01 g/mol
  3. Calculate Mole Ratios: Divide the moles of each element by the smallest number of moles to get the simplest whole-number ratio.

    Mole ratio = moles of element / smallest number of moles

  4. Determine the Empirical Formula: Round the ratios to the nearest whole numbers to get the empirical formula.

Examples

Example 1: Determining Empirical Formula from CHN Analysis

Given: A compound is found to contain 40% carbon, 6.7% hydrogen, and 53.3% nitrogen.

  1. Convert Percentages to Grams:
    • Carbon: 40 grams
    • Hydrogen: 6.7 grams
    • Nitrogen: 53.3 grams
  2. Convert Grams to Moles:
    • Moles of Carbon: 40 g / 12.01 g/mol = 3.33 moles
    • Moles of Hydrogen: 6.7 g / 1.008 g/mol = 6.65 moles
    • Moles of Nitrogen: 53.3 g / 14.01 g/mol = 3.80 moles
  3. Calculate Mole Ratios:
    • Smallest number of moles: 3.33 (for Carbon)
    • Carbon: 3.33 / 3.33 = 1
    • Hydrogen: 6.65 / 3.33 = 2
    • Nitrogen: 3.80 / 3.33 = 1.14 ≈ 1
  4. Empirical Formula: CH₂N

Example 2: Empirical Formula of a Hydrocarbon

Given: A hydrocarbon has 85.7% carbon and 14.3% hydrogen.

  1. Convert Percentages to Grams:
    • Carbon: 85.7 grams
    • Hydrogen: 14.3 grams
  2. Convert Grams to Moles:
    • Moles of Carbon: 85.7 g / 12.01 g/mol = 7.14 moles
    • Moles of Hydrogen: 14.3 g / 1.008 g/mol = 14.19 moles
  3. Calculate Mole Ratios:
    • Smallest number of moles: 7.14 (for Carbon)
    • Carbon: 7.14 / 7.14 = 1
    • Hydrogen: 14.19 / 7.14 = 1.99 ≈ 2
  4. Empirical Formula: CH₂
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