Integrated Science First Term 1st Secondary Grade

What percentage of the Earth's surface is covered by water?

Which of the following is NOT a state of matter that water can exist in?

What is the primary role of the cell membrane in living organisms?

Which component of the hydrosphere is described as water in its gaseous state?

What constitutes the majority of Earth's liquid water?

Which of the following environments is considered part of Egypt's diverse aquatic ecosystems?

What is the term for the frozen water found in polar regions and glaciers?

What is one of the unique properties of water that supports life?

Which process contributes to the formation of clouds in the water cycle?

What is the ratio of hydrogen to oxygen in a water molecule?

What type of bond links the hydrogen atoms to the oxygen atom in water?

Which of the following processes helps form groundwater?

What percentage of a water molecule's mass is contributed by oxygen?

What characteristic of water is indicated by its partial positive and negative charges?

What type of precipitation results from chemical reactions between water vapor and air compounds?

What angle is formed between the two hydrogen atoms in a water molecule?

Aquatic Ecosystem: Chemical Reactions and Water Quality

Water's unique properties support life, including the ability to dissolve many chemicals.
Water exists in three states: solid (ice), liquid, and gas (vapor) within Earth's temperature range.
Essential for life; all living organisms possess a cell membrane that regulates interaction with the environment.
Cell membranes allow water and nutrients to enter cells and facilitate waste removal.

Earth's Water Spheres

Water covers approximately 70% of Earth’s surface, with about 97% of this as salt water in oceans, seas, and salt lakes.
Freshwater sources, crucial for life, are found in rivers, lakes, and underground aquifers.
Water vapor is a key component of the atmosphere.
The cryosphere includes frozen water in polar regions, mountain peaks, and glaciers.
Egypt's aquatic diversity includes the Nile River, Gulf of Suez, Gulf of Aqaba, Red Sea, Mediterranean Sea, and various lakes.

Water Cycle and Its Processes

The water cycle, or hydrological cycle, is a closed system where water constantly moves in different forms.
Major processes include:
- Evaporation: Conversion of water to vapor, contributing to cloud formation.
- Precipitation: Rain or snow falling back to the ground.
- Transpiration and Respiration: Biological processes that release water vapor.
- Infiltration: Water moving through soil and rocks to form groundwater.
Water vapor can chemically react and contribute to acid rain, which affects rock dissolution.

Chemical Structure and Properties of Water

Water (H2O) consists of two hydrogen atoms and one oxygen atom in a 2:1 ratio.
Oxygen comprises 88.89% of the water molecule's mass, while hydrogen constitutes 11.11%.
The molecular structure includes two covalent bonds at a bond angle of about 104.5 degrees.

Chemical Properties of Water

Water is not found in a pure form; it contains various ions and chemical substances.
Polarity: The oxygen atom's higher electronegativity creates partial negative and positive charges within the water molecule.
The polarity leads to unique properties, enabling water to dissolve a variety of substances and participate in chemical reactions.

This quiz covers Chapter 1 of the Integrated Science curriculum for the first term of 1st Secondary Grade. Students will test their understanding of fundamental concepts and prepare for assessments. Answer questions related to various scientific principles introduced in this chapter.