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Unit 2 Notes
Questions on stuff that will be on the Unit 2 test
36
Biology
9th Grade
10/17/2011

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Term
What is an acid?
Definition
A solution that has a higher concentration of hydronium ions (H3O+) then hydroxide ions. (OH-)
Term
What are some properties of acids?
Definition
sour, corrodes metal, if it's acidic enough it burns skin
Term
What is the chemical reaction of water that produces an acid?
Definition
H2O becomes H+ + OH-
Term
What does pH indicate?
Definition
The number of H+ ions and OH- ions in a solution
Term
What simple reaction is acid-base chemistry based on?
Definition
the ionization of water
Term
What is the pH when the # of hydronium and hydroxide ions is the same?
Definition
neutral
Term
What chemical reaction happens when a base is added to water?
Definition

NaOH becomes Na+ + OH-

OH- + H+ becomes H2O

Term
What is a base?
Definition
A solution that has a higher concentration of hydroxide ions (OH-) then hydronium ions (H3O+)
Term
What are some properties of bases?
Definition
bitter, slippery, dissolves grease, irritates eyes and skin
Term
What is another name for basic?
Definition
alkaline
Term
What is an ion?
Definition
an atom with a charge
Term
What mathematical scale is the pH scale based on?
Definition
the logarithmic scale
Term
What is a buffer?
Definition
a substance that resists a change in pH by taking up excess hydrogen ions or hydroxide ions.
Term
What is the pH of blood?
Definition
7.4
Term
What happens if your blood pH became 6.7 or 8.9?
Definition
Too acidic or basic can ruin body functions, causing organs and brain to shut down.
Term
How do we maintain a blood pH of 7.4?
Definition
with buffers such as bicarbonate ions (-HCO3) found in the blood
Term
What do buffers help the body maintain?
Definition
homeostasis
Term
Are buffers neutral?
Definition
No, they are either a weak acid or a weak base.
Term
How are Hydronium and Hydroxide ions formed?
Definition

The hydroxide ion is formed when the oxygen atom in a water molecule takes an electron away from one of its hydrogen atoms so it becomes negatively charged.

The Hydronium ion is formed when the hydrogen atom in a water molecule loses its electron and becomes positively charged.

Term
define Solvent
Definition
The substance in which the solute is dissolved. (It does the dissolving)
Term
define Aqueous Solution
Definition
Solutions in which water is the solvent.
Term
What is adhesion?
Definition
When water molecules stick to surfaces because of surface tension
Term
What is cohesion?
Definition
An attractive force between water molecules that makes them stick together.
Term
What is a chemical reaction?
Definition
When elements combine in ways that cause electrons to become stable.
Term
What is an ionic bond?
Definition
When a positive ion and a negative ion attract each other. (NaCl)
Term
Define aqueous solution
Definition
Solutions in which water is the solvent
Term
Define concentration
Definition
The measurement of the amount of solute dissolved in a fixed amount of the solution.
Term
Define dissociation
Definition
The breaking apart of a water molecule into 2 ions of opposite charge
Term
Define catalysts
Definition
Certain chemical substances that reduce the amount of activation energy that is needed for a reaction.
Term
Define suspensions
Definition
mixtures in which materials do not dissolve in water, but can separate into smaller pieces. (oil)
Term
what is a Hydrogen bond?
Definition
When water molecules, which are polar, are attracted to each other like magnets.
Term
what is Surface tension?
Definition
the "film" that is produced by cohesion in water
Term
Define polar
Definition
The hydrogens have a slight positive charge and the oxygens have a slight negative charge
Term
Define nonpolar
Definition
Molecules that don't have positive and negative ends
Term
Define Capillarity
Definition
When water moves upward against gravity with the help of adhesion and cohesion.
Term
define heat capacity
Definition
The amount of heat required to raise the temperature of a substance one degree.
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