Module 2 Flashcards
What is essential for life and abundant on Earth?
Water
Water is crucial for all known forms of life.
What type of molecule is water and why?
Water is a polar molecule because electrons are not shared equally between the oxygen atom and the hydrogen atoms, resulting in weak positive and negative charges.
This polarity contributes to water’s unique properties.
What results from the interaction between the hydrogen atom of one water molecule and the oxygen atom of another?
Hydrogen bonds
These bonds are responsible for many of water’s unique properties.
What unique properties of water are explained by hydrogen bonds?
- Cohesion
- Adhesion
- Surface tension
These properties are crucial for various biological and ecological processes.
What are the three states in which water exists?
- Solid (ice)
- Liquid
- Gas (steam)
These states can change depending on temperature and pressure.
Why does ice float on water?
Ice is less dense than liquid water
This is why ponds and lakes freeze from the top down.
What property of water allows it to resist rapid temperature changes?
High specific heat
This property is important for regulating temperatures in the environment.
What is the medium of life?
Water
Water is essential for all known forms of life.
What property of water makes it a good solvent?
Water dissolves hydrophilic molecules readily
Hydrophilic molecules interact well with water due to their polar nature.
What happens to hydrophobic molecules in water?
They tend to associate with one another, minimizing contact with water
Hydrophobic molecules are non-polar and do not interact well with water.
What ions does water dissociate into?
H⁺ and OH⁻ ions
This dissociation is fundamental to the chemistry of water.
What determines whether a solution is acidic, neutral, or basic?
The concentration of H⁺ and OH⁻ ions
The balance of these ions dictates the pH of the solution.
What is pH a measure of?
The acidity of a solution
pH quantifies how acidic or basic a solution is.
What is the pH of a neutral solution?
7
Neutral solutions have equal concentrations of H⁺ and OH⁻ ions.
What pH value indicates an acidic solution?
Less than 7
Acidity increases as the pH value decreases.
What pH value indicates a basic solution?
Greater than 7
Basic solutions have a higher concentration of OH⁻ ions.
What do dehydration synthesis reactions do?
They remove water and join smaller molecules to form larger molecules
These reactions create covalent bonds between the smaller molecules.
What do hydrolysis reactions do?
They add a water molecule across a covalent bond and break large molecules into smaller ones
Hydrolysis is the reverse of dehydration synthesis.
