Vernier Software and Technology
Vernier Software & Technology

Determining the Concentration of a Solution: Beer's Law

Introduction

The primary objective of this experiment is to determine the concentration of an unknown nickel (II) sulfate solution. To accomplish this, you will use a Colorimeter or a Spectrometer to pass light through the solution, striking a detector on the opposite side. The wavelength of light used should be one that is absorbed by the solution. The NiSO4 solution used in this experiment has a deep green color, so Colorimeter users will be instructed to use the red LED. Spectrometer users will determine an appropriate wavelength based on the absorbance spectrum of the solution. The light striking the detector is reported as absorbance or percent transmittance. A higher concentration of the colored solution absorbs more light (and transmits less) than a solution of lower concentration.

You are to prepare five nickel sulfate solutions of known concentration (standard solutions). Each is transferred to a small, rectangular cuvette that is placed into the Colorimeter or Spectrometer. The amount of light that penetrates the solution and strikes the detector is used to compute the absorbance of each solution. When a graph of absorbance vs. concentration is plotted for the standard solutions, a direct relationship should result. The direct relationship between absorbance and concentration for a solution is known as Beer’s law.

The concentration of an unknown NiSO4 solution is then determined by measuring its absorbance. By locating the absorbance of the unknown on the vertical axis of the graph, the corresponding concentration can be found on the horizontal axis. The concentration of the unknown can also be found using the slope of the Beer’s law curve.

Objectives

In this experiment, you will

  • Prepare NiSO4 standard solutions.
  • Measure the absorbance value of each standard solution.
  • Find the relationship between absorbance and concentration of a solution.
  • Use the results of this experiment to determine the unknown concentration of another NiSO4 solution.

Sensors and Equipment

This experiment features the following Vernier sensors and equipment.

Option 1

Option 2

Option 3

Option 4

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Chemistry with Vernier »

Chemistry with Vernier

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2Freezing and Melting of Water
3Another Look at Freezing Temperature
4Heat of Fusion of Ice
5Find the Relationship: An Exercise in Graphing Analysis
6Boyle's Law: Pressure-Volume Relationship in Gases
7Pressure-Temperature Relationship in Gases
8Fractional Distillation
9Evaporation and Intermolecular Attractions
10Vapor Pressure of Liquids
11Determining the Concentration of a Solution: Beer's Law
12Effect of Temperature on Solubility of a Salt
13Properties of Solutions: Electrolytes and Non-Electrolytes
14Conductivity of Solutions: The Effect of Concentration
15Using Freezing Point Depression to Find Molecular Weight
16Energy Content of Foods
17Energy Content of Fuels
18Additivity of Heats of Reaction: Hess's Law
19Heat of Combustion: Magnesium
20Chemical Equilibrium: Finding a Constant, Kc
21Household Acids and Bases
22Acid Rain
23Titration Curves of Strong and Weak Acids and Bases
24Acid-Base Titration
25Titration of a Diprotic Acid: Identifying an Unknown
26Using Conductivity to Find an Equivalence Point
27Acid Dissociation Constant, Ka
28Establishing a Table of Reduction Potentials: Micro-Voltaic Cells
29Lead Storage Batteries
30Rate Law Determination of the Crystal Violet Reaction
31Time-Release Vitamin C Tablets
32The Buffer in Lemonade
33Determining the Free Chlorine Content of Swimming Pool Water
34Determining the Quantity of Iron in a Vitamin Tablet
35Determining the Phosphoric Acid Content in Soft Drinks
36Microscale Acid-Base Titration

Experiment 11 from Chemistry with Vernier Lab Book

<em>Chemistry with Vernier</em> book cover

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