5.4 Study Guide Flashcards
List at least 4 of the five properties of water.
Five Properties of Water: Adhesion, Cohesion, Ability as a Solvent, High Specific Heat, High Heat of Vaporization.
Explain the difference between cohesion and adhesion.
While cohesion and adhesion both refer to ‘sticking’ or bonding between molecules, cohesion is sticking between multiple of the same molecule and adhesion is sticking between multiple different molecules.
Define both specific heat and heat of vaporization. Explain why substance temperatures level out during phase changes.
Specific heat is the amount of energy required to increase the temperature of 1 gram of a given substance by 1 degree C. Heat of vaporization is the amount of energy required to shift a given substance from a liquid to a gas.
Explain why water is such a good solvent and state the two types of molecules that it can dissolve.
Water is such a good solvent because it has high polarity, allowing it to exert high amounts of attractive force on polar and ionic particles and easily pull them from each other and dissolve them.
Define Hydronium, Hydroxide, pH, and pOH and explain how they relate both to each other and to acidic and basic substances.
Hydronium (H3O+) and Hydroxide (OH-) are positive and negative ions of water respectively. pH is the potential of hydrogen (hydronium) in a substance and pOH is the potential of hydroxide in a substance. Substances with higher amounts of H3O+ have lower pH and higher pOH levels and are more acidic, while substances with higher amounts of OH- have higher pH and lower pOH levels and are more basic.
Explain why water’s high polarity and ability to form hydrogen bonds make it very cohesive and adhesive.
While water’s high polarity allows it to easily pull apart other molecules, it, along with its ability to form strong hydrogen bonds, also allows it to easily stick to itself and other polar/ionic molecules due to producing high combined attractive and bonding forces.
Explain why water’s high concentration of hydrogen bonds gives it high specific heat and heat of vaporization.
Regarding heat of vaporization, liquids and gases are differentiated by how their molecules are bonded to each other, with liquids having bonds but loose/no set shape and gases having no bonds at all. This means that for water to vaporize, all of the hydrogen bonds between its molecules must be broken, which takes large amounts of energy due to how strong and numerous the bonds are. The same qualities are the reasons for water’s high specific heat as well, as changes in temperature require either the formation or breaking of intermolecular bonds, which take large amounts of energy in water.
Describe why water’s high cohesion and adhesion make it vital to plant life (as well as other organisms).
Water’s ability to stick to itself and other molecules securely makes it a perfect medium to be carried both by itself and with other molecules throughout plant bodies, which must fight against gravity to do so. Water’s high cohesion and adhesion provide enough force for plants to move nutrients throughout their bodies and remain healthy and alive.
Describe why water’s role as a good solvent is vital to both plant and animal life.
Water’s role as a good solvent allows it to be used by plant and animal bodies to dissolve nutrients from food into individual groups and spread them individually throughout the areas they are needed, keeping the organisms alive.
Describe why water’s high heat of vaporization is useful for both plants and animals.
Because water takes so much energy to evaporate, it takes and uses up a lot of heat while going through the evaporation process. This allows plants and animals to remove excess body heat through perspiration, transpiration, and panting or submerging themselves in water, which are all methods of evaporating water around the body and allowing the water to take heat energy with it.
A substance has a pOH of 10. Using this information, supply its pH and its concentrations of H3O+ and OH- in mol/L and state whether it is an acid, base, or neutral.
This substance has a pH of 4 and H3O+ and OH- concentrations of 10^-4 and 10^-10 mol/L respectively, and it is an acid.
A substance has an H3O+ concentration of 10^-11 mol/L. Using this information, supply its pH and pOH and its concentration of OH- in mol/L and state whether it is an acid, base, or neutral.
This substance has a pH of 11, a pOH of 3, and an OH- concentration of 10^-3 mol/L, and it is a base.
How many times higher or lower will the concentration of H3O+ be in a substance with a pH of 4 compared to a substance with a pOH of 6?
Because a pOH of 6 translates to a pH of 8, the substance with a pH of 4 has a 10^4 or 10,000 times higher concentration of H3O+ than the substance with a pOH of 6.
