5.4 Study Guide Flashcards
What are cohesion and adhesion?
Cohesion: bonding between H2O molecules
Adhesion: bonding between H2O and other substances
What is a solvent?
A solvent is a substance that dissolves solutes, which creates solutions.
What are specific heat and heat of vaporization?
Specific heat: The amount of energy it takes to heat up 1g of a substance by 1 degree Celsius
Heat of vaporization: the amount of energy it takes for 1g of water to evaporate to become water vapor, hydrogen bonds must be completely broken
What is concentration?
Concentration is the amount of a substance in a given volume.
What are pH and pOH?
pH= potential of hydrogen/hydronium
pOH= potential of hydroxide
What is a hydroxide ion and what is a hydronium ion?
A hydroxide ion is a negatively charged molecule with an oxygen and a hydrogen atom bonded together.
A hydronium ion is a positively charged molecule with three hydrogen atoms bonded to a single oxygen atom.
What is acid and what is a base?
An acid is a substance with a pH level below 7, a hydronium ion concentration of higher than 10 to the negative 7th, and a hydroxide ion concentration of lower than 10 to the negative 7th.
A base is a substance with a pH above 7, a hydronium ion concentration of lower than 10 to the negative 7th, and a hydroxide ion concentration of higher than 10 to the negative 7th.
What are the five properties of water?
- Cohesion and Adhesion
- Water is the solvent of life
- Ice is less dense than liquid water
- Water has a high specific heat
- Heat of vaporization
How does water’s polarity or ability to make hydrogen bonds give it each its properties?
Water’s polarity allows it to form strong attractions, which allows it to bond with itself and other substances. Water’s high polarity allows it to be attracted to the positive and negative charges in other molecules. This allows water to bond with these molecules, which allows the solute to dissolve in water. In ice, the hydrogen bonds are strong and stable and orient the molecules so that they are further apart than in liquid water. In liquid water, the polar water molecules are constantly forming new bonds as a result of water’s high polarity. This makes ice less dense than liquid water. The hydrogen bonds in water are strong, so they do not break easily. This allows water to resist a change in temperature. Hydrogen bonds hold water together. To evaporate, these bonds must be broken.
How are the properties of water important to living things?
Cohesion and Adhesion: Capillary action (water moving throughout a tree) and surface tension (animals can move or walk on the water)
Water is the solvent of life: Vital for transportation of nutrients
Ice is less dense than water: Allows animals to live under a frozen layer of water. Seasonal turnover.
High specific heat: Coastal areas have more stable temperatures with a smaller temperature range. Inland areas have a greater variation in temperature.
Heat of Vaporization: Organisms rely on evaporative cooling to remove body heat to maintain homeostasis.
What is the pH, [H3O+], [OH-] of a solution when the pOH is 5?
The pH is 9, the [H3O+] is 10^-9, and the [OH-] is 10^-5.
A solution has an [H3O+] concentration of 10^-6. Is it an acid, a base, or is it neutral?
This solution is an acid.
Solution A has a pH of 8 and Solution B has a pH of 3. Compare the concentrations of [H3O+] and [OH-] of the two solutions.
Solution A has a [H3O+] concentration of 10^-8 and Solution B has a [H3O+] concentration of 10^-3. Solution A has a [OH-] concentration of 10^-6 and Solution B has a [OH-] concentration of 10^-11.
