Water Flashcards
What are ionic compounds composed of?
Positive and negative ions
For example, salt is made up of Na+ and Cl- ions.
What happens to ionic compounds when added to water?
The ions are split apart.
Why is water considered a polar molecule?
It has slightly negative oxygens and slightly positive hydrogens.
What is the role of water molecules in the dissolution of ionic compounds?
Water molecules surround and separate the ions.
What is water known as due to its ability to dissolve substances?
The universal solvent.
Why is water’s property as a universal solvent important for biological reactions?
Most biological reactions take place in solution.
In what environments do most biological reactions occur?
In the cytoplasm of eukaryotes and prokaryotes.
How do dissolved substances benefit the body?
They can be transported around the body.
Fill in the blank: Ions can be transported in the _______.
blood plasma.
What is the specific heat capacity of water?
A lot of energy is needed to raise the temperature of 1 gram of water by 1°C
Specific heat capacity can also be defined in terms of 1 kilogram of water.
Why does water have a high specific heat capacity?
Due to the many hydrogen bonds between water molecules that can absorb a lot of energy before being broken
Breaking hydrogen bonds requires significant energy.
What is the effect of water’s high specific heat capacity on temperature changes?
Water is resistant to rapid changes in temperature
This property helps maintain stable temperatures in organisms made up of water.
Fill in the blank: Water’s high specific heat capacity allows the body to remain at a fairly _______.
stable temperature
True or False: The specific heat capacity of water can only be defined for 1 gram of water.
False
It can also be defined in terms of 1 kilogram of water.
What is the result of hydrogen bonding between water molecules?
A lot of energy is needed to evaporate 1 gram of water
This phenomenon is due to the strong hydrogen bonds that hold water molecules together.
What is meant by high latent heat of vaporisation in water?
A lot of energy is required to break the hydrogen bonds to change it from a liquid to a gas
This results in a high boiling point for water.
How does water’s high latent heat of vaporisation benefit organisms?
It allows evaporation of water as a method of cooling without losing too much water
This is crucial for thermoregulation in many organisms.
What happens when water evaporates from the surface of the skin?
It takes heat energy away from the surface, cooling the organism down
This process is essential for maintaining body temperature.
What property of water provides a stable environment for many organisms?
High specific heat capacity and high latent heat of vaporisation
These properties prevent water from changing temperature or evaporating easily.
What happens to water at low temperatures?
Water freezes to form ice
Ice is less dense than liquid water due to the arrangement of water molecules.
Why does ice float on water?
Ice is less dense than water
This is due to water molecules being held further apart in ice.
What effect does ice floating have on ponds and lakes?
Forms an insulating layer at the surface
This insulation prevents the water below from freezing, allowing organisms to survive.
Fill in the blank: Water has a high _______ capacity, which helps maintain a stable environment.
specific heat
True or False: Ice sinks in water.
False
Ice floats because it is less dense than liquid water.
What role does water play in hydrolysis reactions?
Water is used to break down complex molecules
Hydrolysis reactions are essential for digestion and metabolism.
What is released during condensation reactions?
Water is released to join molecules together
Condensation reactions are important in forming polymers.
What process uses water as a raw material?
Photosynthesis
Photosynthesis is crucial for plant life and oxygen production.
Fill in the blank: Hydrolysis reactions use water to ______ complex molecules.
break down
Fill in the blank: Condensation reactions release water to ______ molecules together.
join
True or False: Water is not necessary for photosynthesis.
False
List the three types of reactions that involve water.
- Hydrolysis reactions
- Condensation reactions
- Photosynthesis
What is the tendency of water molecules to stick together called?
Cohesion
Cohesion occurs due to hydrogen bonds between water molecules.
What is the term for water’s tendency to stick to other materials?
Adhesion
Adhesion helps water interact with various surfaces.
How do strong cohesion and adhesion benefit organisms?
They help water flow through organisms, carrying substances along with it
This is crucial for nutrient transport and other physiological processes.
What allows plants to transport water through the xylem in a continuous column?
Cohesion and adhesion
This mechanism is essential for water distribution in plants.
What do water molecules create when they meet air?
A high surface tension
What structure is formed at the surface of the water due to high surface tension?
A skin-like structure
What is the skin-like structure at the surface of the water strong enough to support?
Small organisms such as pond-skaters
True or False: High surface tension in water can support small organisms.
True
Fill in the blank: The skin-like structure formed by water molecules is due to _______.
high surface tension
