Question 1

What are the main differences between acids and bases in terms of their properties?

Accepted Answer

In the context of the IB MYP Science curriculum, acids and bases are distinguished by their chemical properties. Acids typically have a sour taste, can turn blue litmus paper red, and react with metals to produce hydrogen gas. They have a pH less than 7. Bases, on the other hand, have a bitter taste, feel slippery, can turn red litmus paper blue, and have a pH greater than 7. Both acids and bases can conduct electricity when dissolved in water due to the presence of ions.

Question 2

How do acids and bases react to form salts?

Accepted Answer

In chemical reactions, acids and bases can react with each other in a process called neutralization. During this reaction, the hydrogen ions (H⁺) from the acid combine with the hydroxide ions (OH⁻) from the base to form water (H₂O). The remaining ions from the acid and base form a salt. For example, when hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), the products are water and sodium chloride (NaCl), which is a common table salt.

Question 3

What is the role of pH in determining the strength of an acid or base?

Accepted Answer

The pH scale, which ranges from 0 to 14, is used to measure the acidity or alkalinity of a solution. In the IB MYP Science curriculum, understanding pH is crucial for determining the strength of acids and bases. A pH less than 7 indicates an acidic solution, with lower values representing stronger acids. A pH greater than 7 indicates a basic solution, with higher values representing stronger bases. A pH of 7 is considered neutral, which is the pH of pure water.

Question 4

Why are indicators used in experiments involving acids and bases?

Accepted Answer

Indicators are substances used in science experiments to determine the acidity or basicity of a solution. They change color at specific pH levels, providing a visual representation of the solution's pH. Common indicators include litmus paper, phenolphthalein, and bromothymol blue. In the IB MYP curriculum, using indicators helps students understand the concept of pH and the properties of acids and bases through hands-on experiments.

Question 5

Can you explain the concept of a buffer solution in relation to acids and bases?

Accepted Answer

A buffer solution is a special type of solution that resists changes in pH when small amounts of an acid or base are added. It is typically made from a weak acid and its conjugate base or a weak base and its conjugate acid. In the IB MYP Science curriculum, buffer solutions are important for maintaining stable pH levels in various chemical and biological processes. For example, the human body uses buffer systems to maintain the pH of blood, which is crucial for proper physiological function.

Acids, Bases and Salt

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