2.2 Water Flashcards
Why is water referred to as a polar molecule? Oxygen vs hydrogen atom?
Because it has a negative and positive end.
- Oxygen atoms have slightly negative charge while hydrogen atoms have a slightly positive charge
- The electrons are not shared equally between O and H atoms.
- Referred to as the polarity of water
What is the attraction between water molecules? What bond? Weak or strong?
A weak hydrogen bond
What ability of water molecules explain the many properties of water that makes it so important to living things?
The ability of water molecules to form hydrogen bonds
What type of substances dissolve in water?
Hydrophilic, including anything polar molecules such as glucose, and particles with a positive or negative charges such as sodium and chloride ions
Substances that water adheres to, cellulose for example, are also hydrophilic
Why are molecules hydrophobic? What are some examples?
Because they do not have negative or positive charges and are non-polar.
Example: all lipids are hydrophobic, including fats and oils.
How are molecules in the blood transported?
What is an example of a molecules that is carried by the blood plasma?
They are transported by blood plasma which consist of mainly water (95%) plus dissolve substances which transports.
Glucose is a polar molecule hence freely soluble and is able to be transported by the blood plasma.
What are the properties of water? (4)
Adhesive, cohesive, thermal, solvent
What is the adhesion property of water? What’s an example?
Adhesion of water molecules occur when the water molecules are attracted to another polar molecule.
This happens in xylem tissue of plants. The water molecules stick to the walls of the xylem due to the adhesive properties of water.
What is the cohesive property?
What is an example?
Due to its polarity, water molecules are highly cohesive. They stick to one another due to the formation of hydrogen bonds.
Some examples of cohesion are transport of water and plants, surface tension and formation of water droplets.
What are the two thermal property of water?
What is an example?
High specific heat capacity:
This mean it takes a lot of energy to increase the temperature of water and subsequently a lot of energy is given off when it cools. In other words water can absorb or give off a significant amount of heat and maintain a relatively stable temperature.
High heat of vaporization:
This means that water requires a lot of energy to change from a liquid to a gas
What is the solvent property of water?
What’s an example?
The polarity of water allows for many substances to dissolve in it and is an excellent solvent for polar solutes.
Many substances found inside and outside of cells are polar such as nucleic acid, proteins and carbohydrates. Polar molecules that can dissolve in water can be transported around in the blood by a blood plasma.
How do organisms cool their bodies?
Using vaporization as a method of calling cooling (thermoregulation).
With the help of high heat of vaporization property, heat energy is taken away from the body.
How are glucose and amino acids transported in the body?
Both are soluble in water in order for transported by the blood plasma
How are fats and cholesterol transported in the body?
Fats or large non-polar molecules meaning they are insoluble in water. Cholesterol molecules are primarily hydrophobic and are also not soluble in water.
Due to this insolubility they are carried in the water inside liprotein complexes together.
How is oxygen able to be transported in the body?
How is solubility of oxygen affected in water? What does the blood rely on to transport oxygen red blood cells?
Oxygen is nonpolar molecule but it does dissolve in water due to its small size. Only a small amount of oxygen can dissolve in water and it becomes saturated with oxygen at fairly low concentrations.
Solubility of oxygen in water is also affected by temperature. As temperature increases, solubility decreases.
Blood relies on the protein hemoglobin on the surface of red blood cells to adhere to and transport oxygen.
How is sodium chloride transported in water? What happens first?
Sodium is an ionic compound that easily dissolves in water.
Sodium and chloride ions separate and are transport it in the water.
Why does ice float?
As it freezes, the water molecules stop moving, and they’re not able to form as many hydrogen bonds with other water molecules. As a result of not being so close together the density decreases so it is less dense than liquid water that’s why it floats.
How does water being transparent benefit organisms?
Underwater plants are able to photosynthesize
What are hydrophobic interactions?
the forces that cause nonpolar molecules to join together into group in water are known as hydrophobic interactions
What is methane a waste product of?
a waste product of anaerobic respiration in certain prokaryotes that live in habitats where oxygen is lacking
Where do methanogenic prokaryotes live in?
- swamps
- wetlands
- guts of animals (termites, cattle, sheep)
What can methane be used as?
fuel
What does methane contribute to if it escapes into the atmosphere?
greenhouse effect
What are the similarities of water and methane?
- both small molecules
- atoms linked by single covalent bond
What makes water and methanes physical properties very different?
- water molecules are polar and can form hydrogen bonds
- methane are non polar and do not form hydrogen bonds
Which is more dense: water or methane
water
What is the specific heat capacity of methane?
2.2J per g per ˚C
water is 4.2
Comparison of methane and water table
