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⏱️general chemistry ii review

Laboratory buffers

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Laboratory buffers are solutions that resist changes in pH when small amounts of acid or base are added. They typically consist of a weak acid and its conjugate base or a weak base and its conjugate acid, allowing them to maintain a stable pH under varying conditions, which is crucial for many biochemical and chemical reactions.

5 Must Know Facts For Your Next Test

  1. Buffers work by neutralizing small amounts of added acid or base, which helps to stabilize the pH of a solution, making them essential in biological systems.
  2. The effective pH range of a buffer is typically within one unit above and below its pK_a value, which is crucial for selecting the right buffer for specific experiments.
  3. Common laboratory buffers include phosphate buffers, acetate buffers, and Tris buffers, each suitable for different pH ranges and applications.
  4. The choice of buffer components can significantly impact the biochemical processes occurring in an experiment, such as enzyme activity and stability.
  5. Buffers are critical in applications such as cell culture, protein purification, and electrophoresis, where maintaining a consistent pH is vital for successful outcomes.

Review Questions

  • How do laboratory buffers maintain pH stability in biological and chemical reactions?
    • Laboratory buffers maintain pH stability by providing a mechanism to neutralize small amounts of acids or bases that might be introduced during reactions. They consist of a weak acid and its conjugate base or a weak base and its conjugate acid, which can react with any added acids or bases. This property allows them to resist significant changes in pH, ensuring that conditions remain favorable for biochemical processes.
  • Discuss the importance of the Henderson-Hasselbalch equation in selecting an appropriate laboratory buffer.
    • The Henderson-Hasselbalch equation is essential for selecting an appropriate laboratory buffer because it provides a mathematical relationship between the pH of a buffer solution and the ratio of the concentrations of its acid and conjugate base. By knowing the desired pH for an experiment, researchers can choose buffer components that will achieve that pH based on their pK_a values. This understanding helps in designing experiments where pH stability is critical for accurate results.
  • Evaluate how the choice of buffer can impact biochemical reactions in the laboratory setting.
    • The choice of buffer can greatly impact biochemical reactions because different buffers have varying pK_a values and effective ranges. Selecting a buffer that does not match the desired reaction environment can lead to unstable conditions that may affect enzyme activity, protein stability, or the overall outcome of an experiment. For instance, using a buffer outside its effective range may result in drastic changes in pH that could denature enzymes or alter reaction kinetics, leading to erroneous results.