Question

Measurements show that unknown compound X has the following composition:

element mass %
carbon 63.1%
hydrogen 5.29%
oxygen 31.5%
Write the empirical chemical formula of X.

Answer 1

The empirical formula of compound X is C8H8O3.

Step-by-step explanation:

The empirical formula of compound X can be determined by converting the mass percentages of each element to moles, and then finding the simplest whole number ratio between the moles of each element. In this case, the mass percentages are:

• Carbon (C): 63.1%
• Hydrogen (H): 5.29%
• Oxygen (O): 31.5%

To convert the mass percentages to moles, assume 100g of compound X. Then, the moles of each element can be calculated:

• Carbon (C): 63.1g * (1 mol/12.01g) = 5.258 mol
• Hydrogen (H): 5.29g * (1 mol/1.01g) = 5.238 mol
• Oxygen (O): 31.5g * (1 mol/16.00g) = 1.969 mol

The simplest whole number ratio between the moles of each element is:

• Carbon (C): 5.258 / 1.969 ≈ 2.67
• Hydrogen (H): 5.238 / 1.969 ≈ 2.66
• Oxygen (O): 1.969 / 1.969 = 1

Since the ratio cannot have decimals, we need to multiply each ratio by a factor to get whole numbers:

• Carbon (C): 2.67 * 3 = 8
• Hydrogen (H): 2.66 * 3 = 8
• Oxygen (O): 1 * 3 = 3

Therefore, the empirical chemical formula of compound X is C8H8O3.