Explanation

• Organic chemistry is the branch of chemistry that deals with hydrocarbons and their derivatives.
• They are compounds containing carbon and hydrogen atoms.
• It may also contain other elements like oxygen, nitrogen, and sulfur.

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

 The amount of heat required to vaporize one mole of a liquid at its boiling point is called Molar heat of vaporization. 

"Molar" refers to one mole of a substance, and "vaporization" means the process of turning a liquid into a gas. 

Explanation

The substance with the most moles is 3.8 g of H2O (0.211 moles).

Therefore, it has the largest number of molecules. 

Explanation

 The mass of an electron is a standard physical constant in physics.

- Its accepted value is:

  mₑ = 9.109 × 10⁻³¹ kilograms

Explanation

Plasma is the fourth state of matter, following:

1. Solids
2. Liquids
3. Gases

It consists of ionized gases with equal numbers of positively and negatively charged particles.

Explanation

The percentage yield is the most common measure of efficiency in chemical reactions, comparing actual yield to theoretical yield.

Explanation

The stratosphere is the second layer of Earth's atmosphere as you go upwards, lying above the troposphere and below the mesosphere.

The layers of the Earth's atmosphere, in order from the surface, are:

1. Troposphere (up to about 12 km/7.5 miles)
2. Stratosphere (up to about 50 km/31 miles)
3. Mesosphere (up to about 85 km/53 miles)
4. Thermosphere (up to about 600 km/373 miles)

Explanation

Burning wood is a chemical change because it involves combustion.

Wood reacts with oxygen to form new substances, such as ash, carbon dioxide, and water vapor.

Explanation

Elements are placed in order on the periodic table based on their atomic number, how many protons they have.

In a neutral atom, the number of electrons will equal the number of protons, so we can easily determine electron number from atomic number.