Water Flashcards
What is water?
Water has many unique properties. These make it very different from other compounds.
-Water in a solid state is less dense than water in a liquid state, which is important to life in lakes.
What is meant by water is polar?
- Water has a bent shape.
- The electrons are not shared evenly in O-H bonds.
- Oxygen attracts the electrons more strongly.
- Oxygen has a permanent partial negative charge.
- Hydrogen has a permanent partial positive charge.
- Water is a polar molecule: Oxygen end is negative and the hydrogen end has a positive.
- Polar molecules also called a dipole.
What are hydrogen bonds?
- Water molecules attract one another because they are polar.
- Hydrogen bonds are formed: an oxygen atom from one water molecule is attracted to a hydrogen atom in another molecule.
- Hydrogen bonds are an intermolecular force: The force between molecules.
- An intramolecular force: A force within molecules(covalent bond) aka cohesive force.
- Hydrogen bonds are the strongest of intermolecular forces but are much weaker than intramolecular forces aka adhesive force.
What are the properties of water?
- The boiling point and melting point of water is higher than similar substances because it takes more energy to break hydrogen bonds.
- It requires a great deal of energy to increase the temperature of water because it takes more energy to spreed molecules because of hydrogen bonding.
- Water has a concave meniscus(curved) and shows capillary action the strong attraction between polar molecules(hydrogen bonding).
- Ice floats in water because water expands when it freezes because water molecules arrange in pattern held by hydrogen bonds.
- Water has high surface tension because hydrogen bonds pull molecules on surface into smallest possible area.
Water is the only substance on earth that exists in _______ in all ______ states.
Large quantities, three.
Explain how the shape of a water molecule contributes to its unusual properties.
Water is polar. It has a partial negative oxygen end and a partial positive hydrogen end.
Explain how the bonding with a water molecule contributes to its unusual properties.
The permanent difference in partial charge between the oxygen and hydrogen in water makes it a polar molecule(dipole).
Because of oxygen’s high electronegativity, electrons shared between an oxygen atom ans a hydrogen atom spend most of their time around the _____ oxygen. As a result, there is a partial ______ charged around the oxygen while there is a partial ______ charge around the hydrogen. A water molecule is said to be ______ or possesses________.
Oxygen, negative, positive, polar, a dipole.
Since water molecules are ______, the ______ hydrogen end of one molecule is attracted to the _______ oxygen end of another water molecule. This results in the formation of ______ _______.
Polar, positive, negative, hydrogen bonds.
An intermolecular force acts ______ molecules; an example of this type of force is a _________.
Between, hydrogen bond.
An intramolecular force acts ________ molecules; an example of this type of force is a _________.
Within, covalent bond.
In general, _______ bonds are much stronger than _______ bonds.
Covalent, hydrogen.
Why are the boiling point and melting point of water so much higher than those of other substances?
It takes a lot of energy to break the hydrogen bonds between the water molecules.
Why does water have a high specific heat capacity?
It takes a lot of energy to make the water molecules move more quickly because of the hydrogen bonds.
Why do we sweat after exercising?
Sweating helps to cool the body as it takes a great deal of body heat energy to cause sweat to evaporate.
