Bio I - 3 Flashcards
 What is the biological medium on earth?
Water
What does the structure of the water molecule allow?
It allows water molecule to interact with other molecules
What are the three phases of matter and list their properties:
Solid - hold shapes and fixed volume
Liquid - shape of container, free surface, and fixed volume
Gas - shape of container and volume of the container
In the water molecule where do the electrons of the polar covalent bonds tend to be?
By the oxygen
What is a polar molecule and what is an example of a polar molecule?
The overall charge is unevenly distributed
Water 
 What are the four properties of water?
- Cohesive behavior
- Ability to moderate temperature
- Expansion upon freezing
- Versatility as a solvent
What is cohesion?
When hydrogen bonds hold water molecules together
What is adhesion?
Adhesion is an attraction between different substances
What is surface tension?
It is a measure of how hard it is to break the surface of a liquid
Does water have a high or low surface tension and why?
Water has a high surface tension due to hydrogen bonding between the molecules at the air water interface and to the water below
What does water do with the heat that it absorbs from warmer air?
It releases the stored heat to cooler air
When water absorbs or releases a large amount of heat, does it change in its own temperature? 
Slightly
What is kinetic energy?
the energy of motion
What is thermal energy?
It is the kinetic energy associated with random motion of atoms or molecules
What is temperature?
It is a measure of energy that represents the average kinetic energy of the molecules in a body of matter
What is heat?
Thermal energy and transfer from one body of matter to another is defined as heat
What is a calorie
It is the amount of heat required to raise the temperature of 1 g of water by 1°C
What are kilo calories?
The calories on food packages where 1 kg calorie equals 1000 calories 
What is a joule?
It is another unit of energy where one joule equals 0.239 cal or 1 cal equals 4.184 joule
What is the definition of temperature?
The average kinetic energy of the structural elements of a system
What are the values of temperature?
Positive and negative
What are the units of measurement for temperature?
Celsius, kelvin, and Fahrenheit
Does the temperature depends on the quantity of the substance?
No it is related to the average kinetic energy of the particles
What is the definition of thermal energy?
The total kinetic energy of the structural elements of a system
What are the values of thermal energy?
Always positive
What are the units of measurement for thermal energy?
Joule and calorie 
Does thermal energy depend on the quantity of the substance?
Yes it is related to the total kinetic energy of the particles
What is specific heat?
It is the amount of heat that must be absorbed or lost for 1 g of that substance to change its temperature by 1°C
What is the specific heat of water?
1 cal/g/Celsius
Why does water resist changing its temperature?
Because of its high specific heat
What is evaporation?
It is the transformation of a substance from liquid to gas
What is heat of vaporization?
It is the heat a liquid must absorb for 1 g to be converted to gas
What is evaporative cooling?
It is when a liquid evaporates and its remaining surface cools
Why does ice float in liquid water?
Because hydrogen bonds in ice are more ordered making ice less dense than water
What does water reach its greatest density at?
4°C
What would happen if ice sank?
All bodies of water would eventually freeze solid making life impossible on earth
What causes global warming?
Carbon dioxide and other greenhouse gases
What is a solution?
It is a liquid that is completely homogeneous mixture of substances
What is a solvent?
It is a dissolving agent of a solution
What is a solute?
It is a substance that is dissolved
What is an aqueous solution?
It is one in which water is a solvent
What kind of molecules can water dissolve?
Nine ionic polar molecules and polar molecules
What do most chemical reactions involve?
Solutes dissolved in water
What does hydrophilic mean?
It is one that has an affinity for water
What does a hydrophobic substance mean?
It is one that does not have an infinity for water
Are oil molecules hydrophobic or hydrophilic and why?
Hydrophobic because they have relatively nonpolar bonds
What are hydrophobic molecules related to oils major ingredients for?
Cell membranes
What happens when a hydrogen atom leaves its electron behind?
Is transferred as a proton or hydrogen ion H+
What is the molecule called that lost the proton given to the hydrogen ion?
Hydroxide ion OH-
What is a state of dynamic equilibrium?
When water molecules dissociate at the same rate at which they are being reformed
True or false concentration of hydrogen ions and hydroxide ions are equal and pure water
True
What modifies the concentration of hydrogen ions and hydroxide ions?
Adding solutes called acid and bases
What is the pH scale?
It is used to describe whether a solution is acidic or basic
What is an acid?
Any substance that increases the hydrogen ion concentration of a solution
What is a base?
Any substance that reduces the hydrogen ion concentration of a solution
What do weak acids and bases do?
They reversibly release and accept back hydrogen ions but can still shift the balance of hydrogen ions and hydroxide ions away from neutrality
Do acidic solutions have pH values lesson seven?
Yes
True or false basic solutions have a pH values greater than seven
True
What do most biological fluids have for their pH value?
Between 6 to 8
What must the internal pH of most living cells remain at or close to?
7
What is a buffer?
A buffer is a substance that minimizes changes in concentration of hydrogen ions and hydroxide ions in a solution
What do most buffer solutions contain?
A weak acid and it’s corresponding face which combined reversably with hydrogen ions
