bio 2.01 properties of water
Define covalent bond.
A bond that forms when two atoms overlap their outer energy levels in order to share pairs of valence electrons.
What is a covalent compound?
A compound made up of atoms that are covalently bonded together
What is an ionic compound?
A compound made up of atoms that are ionically bonded together.
Describe capillary action and give an example.
Capillary action is movement of water through a narrow tube. Ex: water going up plant stems
Describe surface tension and give an example
Surface tension is a measure of how difficult it is to stretch or break the surface of a liquid. Ex: insects walking on water
Describe hydrogen bonding.
The charged ends of one water molecule are attracted to the oppositely charged regions of its neighboring water molecules.
What are the two main types of chemical bonds?
ionic and covalent bonds.
What is density?
its a ratio of mass to volume.
What is specific heat?
the amount of energy needed to change the temperature of 1 gram of a substance by 1 degree Celsius.
What is heat of vaporization?
the amount of heat energy needed to convert 1 gram of a liquid into a gas.
Define ionic bond.
the attraction of a positively charged ion to a negatively charged ion
What is being measured in pH?
the concentration of hydrogen ions in a solution.
What is the pH of water?
7
What is the range of the pH scale?
0-14
What types of substance have pH values less than 7?
Acids
Describe adhesion and give an example.
Adhesion is the attraction of water to a different substance. Ex: water on leafs
What types of substance have pH values greater than 7?
Bases
Give an example of a substance with a high concentration of H+ ions.
Battery acid
Describe cohesion and give an example.
Cohesion is an attraction of same particles. Ex: water
What is the chemical formula for water?
H20
What type of bonds and atoms form a water molecule?
Hydrogen atoms and oxygen atoms.
What happens when water freezes?
It expands
Why is ice less dense than liquid water?
Its specific arrangement requires more space than the arrangement of water molecules in liquid water.
Give an example of a substance with a low concentration of H+ ions.
Liquid drain cleaner
Define vaporize.
To convert a substance from a liquid to a gas
In the specific heat example, which liquid has the highest specific heat? (Remember that the more heat it takes to make the liquid raise 1 degree in temperature, the higher the specific heat it has.)
Water
Why is it important to ecosystems that ice floats in liquid water?
Without it, lakes and ponds would freeze from the bottom up, killing the marine life and destroying those ecosystems.
Does water have a high heat of vaporization?
Yes
Does water have a high specific heat? What does this mean?
Yes, it means it can absorb or release a relatively large amount of heat with only a small change in its temperature.
Why is water considered to be a universal solvent?
because many different substances dissolve well in water.
Why does water have a high boiling point?
because of the hydrogen bonding that holds the molecules together.
