Water and pH Flashcards
As pH rises, a substance gets more
Basic
As pH lowers, a substance gets more
Acidic
What is it called when water splits into ions?
Disassociation
When water disassociates, it splits into…
Equal numbers of H+ (hydrogen) and OH- (hydroxide) ions
An acid has
more H+ (hydrogen) ions
A base has
fewer H+ (hydrogen) ions or more HO- (hydroxide) ions
What is a buffer?
A substance that resists a change in pH
What happens when acids disassociate?
They release more H+ than OH-, depending on how acidic they are
What happens when bases disassociate?
They release OH- or take in H+, with amounts depending on how basic they are
The pH scale is a negative logarithm. What does this mean?
The scale decreases by powers of 10, meaning that 8 is 10 times less than 7, for example (the numbers refer to concentrations of hydrogen ions, beginning with 0% at 1 on the scale)
Blood Buffer System: H2CO3 <> H+ + HCO3-
How would you lower the pH of the blood?
Move the equation to the right, releasing H+ ions and acidifying the blood
Blood Buffer System: H2CO3 <> H+ + HCO3-
How would you raise the pH of the blood?
Move the equation to the left, taking in H+ ions and making the blood more basic
A water molecule…
Is made up of two hydrogens and one oxygen atom covalently bonded with a pH of 7. The oxygen has a negative electrostatic charge while the hydrogens are slightly positive
Cohesion
The ability of water or another substance to stick to itself, allowing surface tension
Adhesion
The ability of water to stick to other (hydrophilic) substances
Hydrophobic
A nonpolar or nonionized substance that repels water
Hydrophilic
A polar or ionized substance that sticks to or easily mixes with water
High heat of vaporization
Water takes a lot of energy to evaporate – this is used by organisms to maintain body heat through sweating
High heat capacity
Water resists changes in temperature – this moderates coastal climates
Unique density
Water is less dense as ice than as water, meaning that it can float on itself – this is used by organisms who live underwater in the winter when the surface freezes
Nearly Universal Solvent
Water can dissolve all polar substances
Solvent, solute, and solution
Solvent: A liquid that dissolves another substance
Solute: a solid that is dissolved in a solvent
Solution: a solvent dissolved in a solute
