Lactic acid is a substance that forms in muscle tissue during physical activity and is responsible for muscle soreness. An elemental analysis of this compound shows that it contains 40.0 mass % C, 6.71 mass % H and 53.3 mass % O. What is the empirical formula for Lactic acid?

Question

Quizplus · Accepted Answer

To find the empirical formula, we convert the mass percentages to moles by assuming a 100 g sample. This gives us 40.0 g of C, 6.71 g of H, and 53.3 g of O. Using the atomic masses (C = 12.01 g/mol, H = 1.008 g/mol, O = 16.00 g/mol), we find the moles of each element: C = 40.0 g / 12.01 g/mol = 3.33 mol, H = 6.71 g / 1.008 g/mol = 6.66 mol, O = 53.3 g / 16.00 g/mol = 3.33 mol. The ratio of C:H:O is approximately 1:2:1, making the empirical formula CH2O. However, the options provided seem to use a subscript notation that doesn't directly translate to standard chemical notation. The correct choice, based on the calculation, should represent the empirical formula CH2O, but none of the provided options accurately reflect this in standard chemical notation. Given the options, A seems to be intended as the correct answer, but it's important to note the discrepancy in notation.

Lactic Acid Is a Substance That Forms in Muscle Tissue