Chemistry Regents Practice Test 2025 – The All-in-One Guide to Exam Success!

A spectrophotometer is an analytical instrument specifically designed to measure the intensity of light at various wavelengths as it passes through a sample. This device operates on the principle that different substances absorb light differently based on their molecular structure. By measuring how much light is absorbed at particular wavelengths, a spectrophotometer can provide crucial information about the concentration of a solute in a solution, as well as insights into the properties of the substance being studied.

The reason other options do not apply is that a spectrophotometer does not measure mass, temperature, or pH. Measuring mass requires a balance, temperature is assessed with a thermometer, and pH levels are determined using a pH meter or indicator paper. Therefore, its primary function centers on analyzing light absorption across different wavelengths, making it a vital tool in various scientific fields, particularly in chemistry and biochemistry.