Lesson 2 Flashcards
How many protons & electrons does water have ?
10 protons
10 electrons
Neutral
What charges does H2O have ?
Partial negative charge and partial positive charge
A molecule in which the charges are unevenly distributed is said to be ….
“Polar”
Why can polar molecules like water attract each other ?
Because of their partial positive and partial negative charges
What is a hydrogen bond ?
Attraction between hydrogen atom with partial positive and partial negative charge
What are the most common partially negative atoms involved in hydrogen bonding
Oxygen, nitrogen, fluorine
Where is the negative pole in the water molecule ?
Near the oxygen atom
Where is the positive pole of the water molecule located ?
Between the hydrogen atoms
What is water able to do because it is a polar molecule ?
Form multiple hydrogen bonds
What is cohesion ?
Attraction between molecules of the same substance
What causes water molecules to be drawn together
Cohesion
What does cohesion produce ?
Surface tension
What is adhesion ?
Attraction between molecules of different substances
What is heat capacity ?
Amount of heat energy required to increase temperature.
What is a mixture ?
Material composed of two or more elements or compounds physically mixed together but not chemically combined.
What is an example of a mixture ?
Sugar and sand ; salt and pepper
What are two mixtures that can be made with water ?
Solutions suspensions
What is a solution ?
Mixture when components are evenly distributed
What is an example of a solution ?
Table salt and water
What is a solute ?
Substance that is dissolved in solvent (salt)
What is a solvent ?
Substance in which the solute dissolves (water)
Water is polar so it can dissolve what ?
Ionic compounds and other polar molecules
What is the greatest solvent on earth ?
Water
When is a solution saturated ?
When a given amount of water has dissolved all of the solute it can.
What is a molecule that does not dissolve but instead separates into smaller pieces ?
Suspensions
What are the most important biological fluids ?
Suspensions and solutions
What is formed when water molecules split apart ?
Ions
What does the pH scale indicate ?
The amount of hydrogen ions in a solution
What does pH stand for ?
Power of the hydrogen atom
What does below 7 on the oH scale indicate ?
Acidic
What does above 7 on the pH scale indicate ?
Base of alkaline & corrosive
What is 7 on the pH scale ?
Neutral
What is an acid ?
Compound that forms hydrogen ion in solution
What is a base ?
Compound that produces hydroxide ions in solution
Why are buffers ?
Weak acids or bases that can react with strong acids or bases to prevent sudden changes.
