What's the purpose of a calibration curve?

A calibration curve is used to determine the concentration of a substance in an unknown sample by comparing it to a set of standard samples.

A calibration curve, also known as a standard curve, is a type of graph used in analytical chemistry. It is a tool that allows scientists to determine the concentration of an unknown substance in a sample. This is achieved by comparing the unknown sample to a series of standard samples of known concentration. The curve is created by plotting the response of the instrument (like absorbance in spectroscopy or current in electrochemistry) against the concentration of the standard samples.

The calibration curve is a crucial part of many laboratory procedures. It is used in a wide range of scientific fields, including environmental science, pharmaceuticals, forensics, and food analysis. The curve is typically linear, but it can also be non-linear depending on the nature of the reaction or process being studied.

To create a calibration curve, a series of standard solutions are prepared with known concentrations of the substance of interest. These solutions are then measured using the appropriate analytical technique. Understanding the basics of collision theory can enhance the interpretation of these measurements. The instrument's response to each standard solution is recorded and plotted on the y-axis of the graph, while the known concentrations are plotted on the x-axis. The points are then connected to form the calibration curve.

When an unknown sample is measured, its response can be compared to the calibration curve to determine its concentration. This is done by finding the point on the y-axis that corresponds to the response of the unknown sample, and then drawing a line to the x-axis. The point where this line intersects the x-axis gives the concentration of the unknown sample. Additionally, understanding how to effectively plot data can significantly improve the accuracy of such measurements.

In conclusion, a calibration curve is an essential tool in analytical chemistry. It provides a reliable and accurate method for determining the concentration of an unknown sample. By comparing the response of the unknown sample to a series of standard samples, scientists can accurately determine the concentration of a substance in a sample. Moreover, the role of enthalpy changes in chemical reactions can further contextualise the reactions observed during the calibration process.