Explanation

Global warming is primarily caused by the increasing levels of carbon dioxide (CO2) in the Earth's atmosphere, which traps heat and leads to a warming effect.

The main reason for this increase is human activities such as:

• Burning fossil fuels like coal, oil, and gas
• Deforestation and land-use changes

Explanation

• If the pH value is greater than 7, the solution is basic (also known as alkaline).
• This means that the concentration of hydroxide ions (OH-) is higher than the concentration of hydrogen ions (H+).

Key Points:

• pH < 7: Acidic
• pH = 7: Neutral
• pH > 7: Basic (or alkaline)

Explanation

Fats are typically solids at ordinary room temperature (around 20-25°C or 68-77°F).

However, they can melt and become liquids when heated to a higher temperature.

Explanation

The functional group -COOH is the carboxyl group, which is a characteristic functional group of carboxylic acids.

Carboxylic acids are a class of organic compounds that contain this group, examples include:

• Formic acid (HCOOH)
• Acetic acid (CH3COOH)
• Citric acid (C6H8O7)

Explanation

Water (H₂O) is a polar solvent due to its asymmetrical molecular structure.

It results in a slightly positive charge on the hydrogen atoms.

A slightly negative charge on the oxygen atom.

Explanation

Citric acid is a natural preservative and flavoring agent that is commonly used in foods and beverages to add a sour taste.

It is particularly useful in cold drinks, such as:

• Soft drinks (e.g., lemon-lime soda)
• Fruit juices (e.g., orange, grapefruit)
• Sports drinks
• Energy drinks

Explanation

KCl (potassium chloride) is a salt.

Specifically a neutral salt formed by the reaction of an acid (HCl) with a base (KOH).

Explanation

CN (cyanide ion) is a Lewis base.

Because it donates an electron pair to form a coordinate covalent bond.

Explanation

Approximately 70% of the Earth's surface is covered with water.

This includes oceans, seas, lakes, rivers, and other bodies of water.

Explanation

Oxygen (O2) is not a greenhouse gas.

Greenhouse gases are gases in the Earth's atmosphere that absorb and emit radiation, trapping heat and contributing to the Greenhouse Effect.

The main greenhouse gases are:

• Carbon dioxide (CO2)
• Methane (CH4)
• Nitrous oxide (N2O)
• Water vapor (H2O)
• Ozone (O3)
• Chlorofluorocarbons (CFCs)
• Hydrofluorocarbons (HFCs)
• Perfluorocarbons (PFCs)