Acids, Bases & Buffers
Acids, bases, and buffers are fundamental concepts in chemistry. Acids are substances that release hydrogen ions (H⁺) in solution, while bases release hydroxide ions (OH⁻) or accept H⁺. They play crucial roles in chemical reactions and biological processes. Buffers are solutions that resist changes in pH when acids or bases are added, maintaining stable conditions in living organisms and chemical systems by neutralizing excess H⁺ or OH⁻ ions.
Acids, Bases & Buffers
Acids, bases, and buffers are fundamental concepts in chemistry. Acids are substances that release hydrogen ions (H⁺) in solution, while bases release hydroxide ions (OH⁻) or accept H⁺. They play crucial roles in chemical reactions and biological processes. Buffers are solutions that resist changes in pH when acids or bases are added, maintaining stable conditions in living organisms and chemical systems by neutralizing excess H⁺ or OH⁻ ions.
💡 Key Takeaways
- Explain what acids and bases are, including how acids donate H+ and bases accept H+ or release OH− in solution.
- Describe pH, the pH scale, and how acid/base strength influences solution pH.
- Explain neutralization reactions where acids react with bases to form water and a salt.
- Define buffers, how they resist changes in pH, and recognize common biological and everyday buffer systems.
❓ Frequently Asked Questions
What is a Brønsted–Lowry acid and base?
In Brønsted–Lowry theory, an acid donates a proton (H+), while a base accepts a proton. During a reaction, the acid transfers H+ to the base.
What is pH and what does it indicate about acidity or basicity?
pH measures the hydrogen ion concentration. Lower pH means more acidic, higher pH means more basic; 7 is neutral. Each unit represents a tenfold change in [H+].
How do buffers resist changes in pH?
A buffer contains a weak acid and its conjugate base (or a weak base and its conjugate acid). When small amounts of acid or base are added, the system shifts to neutralize it, keeping pH relatively stable.
What is the difference between strong and weak acids/bases?
Strong acids/bases dissociate completely in water, producing many ions. Weak acids/bases only partially dissociate, establishing an equilibrium and yielding fewer ions.
Why are buffers important in biology? Can you name an example?
Buffers maintain stable pH in biological systems, essential for enzyme activity and metabolism. Example: the bicarbonate buffering system in blood keeps pH around 7.35–7.45.