Chapter 2 Flashcards
What are the characteristics (charge and location) of these sub-atomic particles: protons, electrons and neutrons?
1.Protons are positive in the nucleus
2. Neutrons are in the nucleus and doesn’t have a charge
3. Electrons are negative and outside the nucleus
What determines the reactivity of atoms?
The amount of atoms in the outer shell
Which atom is more reactive and why: oxygen or fluorine?
Fluorine because Fluorine needs one more electron, oxygen needs more than 1 electron. (The fuller the outer shell is the less reactivate it will because it’s stable. The less electrons on the outer shell will be more reactive because they are unstable and looking for electrons).
What are isotopes?
Isotopes are atoms with the same protons but different masses, theres a different amount of neutrons.
How are electrons shared in nonpolar covalent bonds, polar covalent bonds, and ionic bonds (give examples of each)?
Non covalent bonds are shared equally, polar bonds aren’t shared equally, ionic bonds form even if the charges are opposite.
What is electronegativity, and how is the difference in electronegativity between two atoms used to determine the type of bond they are likely to form?
Electronegativity is when an atom attracts bonding electrons to itself, smaller results are covalent bonds, the larger is ionic bonds.
What are the properties of water that make it an excellent solvent?
Polarity and able to form hydrogen bonds, homogenous mixture, unequal because its polar.
What structural features and biochemical properties of water make it important for living organisms?
- Used as solvent for many substances
- Helps transports cells
- Uses nutrients and oxygen
- More abundant molecules
- Polarity
- Hydrogen bonds and Covalent Bonds
Describe examples of adhesion, cohesion, and surface tension.
- Adhesion- forms hydrogen bonds with other substances
- Cohesion- form Hydrogen bonds with itself
- Surface tension- water molecules are tighter than the air molecules,this forms a water droplet
How does hydrogen bonding facilitate the ability of water molecules to be an excellent solvent?
Hydrogen bonds structure is asymmetrical and small so its easy for water to interact with other polar molecules. (Has a high electronegativity)
Why is liquid water more dense than solid water?
Liquid water is more dense as liquid water molecules expand when it becomes a solid. When its liquid the molecules are closer together, more compact and that is what density is (connection to surface tension)
What does the pH scale measure?
The pH scales measure H+ and OH-, measuring concentration of hydrogen ions
What is the difference between specific heat and heat of vaporization and why does water have a high value for both of these? How is this helpful for living organisms?
The difference between specific heat is the amount of heat needed to increase the temperature. Heat of vaporization, is the energy is take for liquid water to turn into water vapor. Water has a high value for both of these because of hydrogen bonds. Hydrogen bonds, forming and breaking are examples of specific heat and water vapor.
What defines a substance as an acid or a base and how does the pH value express this?
pH measures the amount of hydrogen ions, acid is the higher H+, bases have more OH-
What role do buffers play in pH stabilization?
Buffers absorb excess H+ and or OH-, maintain a narrow range, needed for survival. Buffers also doesn’t let things get backed up, that will challenge our survival.
