UNIT C

What is the definition of an acid?

Acids are substances that release hydrogen ions (H+) when dissolved in water.

What are the properties of acids?

Acids taste sour, can conduct electricity in solution, react with metals to produce hydrogen gas, and turn blue litmus paper red.

Can you name three examples of acids?

Examples of acids include hydrochloric acid (HCl), sulfuric acid (H2SO4), and acetic acid (CH3COOH).

What is the definition of a base?

Bases are substances that release hydroxide ions (OH−) when dissolved in water.

What are the properties of bases?

Bases taste bitter, feel slippery, can conduct electricity in solution, do not react with metals, and turn red litmus paper blue.

Can you name three examples of bases?

Examples of bases include sodium hydroxide (NaOH), ammonia (NH3), and calcium hydroxide (Ca(OH)2).

What does the pH scale measure?

The pH scale measures how acidic or basic a solution is, ranging from 0 to 14.

What do the pH values indicate?

A pH of 0 to 6 indicates acidity, a pH of 7 indicates neutrality, and a pH of 8 to 14 indicates basicity.

How does each step on the pH scale represent a change?

Each step on the pH scale represents a tenfold change in acidity or basicity.

What is the pH of lemon juice?

Lemon juice has a pH of around 2, indicating it is acidic.

What is the pH of pure water?

Pure water has a pH of 7, indicating it is neutral.

What is the pH of baking soda?

Baking soda has a pH of around 9, indicating it is basic.

What is neutralization?

Neutralization is a chemical reaction between an acid and a base, producing water (H2O) and a salt.

Can you provide the general equation for neutralization?

The general equation for neutralization is: Acid + Base → Water + Salt.

What is an example of a neutralization reaction?

An example of a neutralization reaction is hydrochloric acid (HCl) reacting with sodium hydroxide (NaOH) to produce water (H2O) and sodium chloride (NaCl).

How can you measure pH using litmus paper?

Red litmus paper turns blue in a base, while blue litmus paper turns red in an acid.

What is a pH meter?

A pH meter is a device that provides a precise digital pH reading of a solution.

What is a universal indicator?

A universal indicator is a liquid or paper that shows a range of colors depending on the pH level of a solution.

What role does lightning play in the nitrogen cycle?

Lightning splits nitrogen molecules (N2) in the atmosphere, allowing them to react with oxygen to form nitrogen oxides (NO, NO2).

What happens to nitrogen oxides after they are formed by lightning?

Nitrogen oxides dissolve in rainwater to form nitrates (NO3−), which are then absorbed by plants.

How does nitrogen fixation by lightning benefit plants?

Nitrogen fixation by lightning converts atmospheric nitrogen into a usable form (nitrates) that plants absorb to make proteins and other essential molecules.

What is the temperature of lightning bolts?

Lightning bolts can produce immense heat and energy, reaching temperatures of up to 30,000°C (54,000°F).