Chapter 3 Flashcards
Polarity of the Water Molecule
The water molecule is polar because the electrons spend more time near oxygen than hydrogen, which allows molecules to form hydrogen bonds with eachother
What are the five emergent properties of water?
- Cohesive behavior 2. Adhesive Behavior 3. Ability to moderate temperature 4. Expansion upon freezing 5. Versatility as a solvent
What is cohesion?
Hydrogen bonds hold water molecules together, which is cohesion
What is adhesion?
The attraction between different substances, for example between water and plant cell walls
Moderation of temperature by water
water absorbs heat from warmer air and releases stored heat to cooler air, water can absorb or release a large amount of heat
define kinetic energy
kinetic energy is the energy of motion
define thermal energy
the kinetic energy associated with random motion of atoms or molecules, it is referred to as heat if it transferred from one body of matter to another
what does temperature measure?
temperature is a measure of energy that represents the average kinetic energy of the molecules in a body of matter
what is a calorie?
a calorie is the amount of heat required to raise the temperature of 1 gram of water by 1 degree celsius
what is specific heat?
the amount of heat that must be absorbed or lost for 1 gram of that substance to change its temperature by 1 degree celsius
what is water’s specific heat?
1 cal/ gram/ degrees celsius
when is heat absorbed or released in terms of hydrogen bonds?
heat is absorbed when hydrogen bonds break, heat is released when hydrogen bonds form
What is evaporative cooling?
As a liquid evaporates, its remaining surface cools, which can help stabilize temperatures in organisms and bodies of water
What is a solvent vs a solute?
A solvent is the dissolving agent of a solution and a solute is what is being dissolved
How does salt dissolve in water?
When an ionic compound is dissolved in water, each ion is surrounded by a sphere of water molecules called a hydration shell
What is a hydrophilic substance?
One that has an affinity for water, loves water
What is a hydrophobic substance?
One that does not have an affinity for water, hates water
What is Molarity (M)?
the number of moles of solute per liter of solution,
What happens when a hydrogen atom in a hydrogen bond between two water molecules shifts from one to the other?
The hydrogen atom that leaves the electron behind is transferred as a proton and becomes a hydrogen ion (H+). The molecule that lose the proton is now a hydroxide ion (OH-). The molecule with the extra proton is now a hydronium ion (H3O+)
What is used to describe whether a solution is acidic or basic?
the pH scale
how are concentrations of H+ and OH- in pure water?
the concentrations are equal
what is an acid?
an acid is any substance that increases the H+ concentration of a solution
what is a base?
a base is any substance that reduces the H+ concentration of a solution
Acidic solutions vs Basic on pH scale
Acidic solutions are less than 7, and basic solutions are greater than 7
