BY 123 SI worksheet
Wednesday, Sep. 2nd 2015
True or false? In a covalent bond each of the atoms in the bond gains its own set of 8 electrons, completing its octet.
False. The bond will share electrons so there are still a total of 8 electrons being shared between the two atoms.
What is the difference between a polar and nonpolar covalent bond?
Atoms in polar bonds have equal electronegativity so electrons are equally shared between the atoms. Polar bonds have unequal electronegativity so electrons are not shared equally, creating regions of partial positive or partial negative charge.
Is water polar or nonpolar?
Polar
What is the difference between a cation and an anion?
A cation is an ion with a positive charge (fewer electrons) and an anion is an ion with a negative charge (more electrons)
Why is a hydrogen bond not technically a “bond?”
Because hydrogen bonds come from the attraction of partial positive and partial negative charges meaning that no electrons are shared or donated, thus no bond.
What are the four characteristics of water that make it so important to life on earth?
Temperature regulation
It’s a universal solvent
It is less dense in its solid form than its liquid form
Cohesion and adhesion
Explain the difference between cohesion and adhesion
Cohesion is the ability of water to stick to itself and adhesion is the ability of water to stick to other surfaces.
What does it mean when water has a high “specific heat?”
Specific heat is the amount of energy required to heat one gram of water one degree Celsius, which for water is one calorie. Water has a high specific means its good at moderating temperature.
Why does the evaporation of water cool a surface?
Water absorbs latent heat from the surface that it is on while it is being vaporized (evaporated), cooling the surface.
Why does solid ice float on top of liquid ice?
Because when water freezes if forms a crystal lattice. The molecules slow down and hydrogen bonding takes over to form the lattice. This structure has the molecules spaced farther apart than liquid water. This makes ice less dense than water and allows it to float.
What is the difference between a solute, a solvent, and a solution?
A solute is dissolved in a solvent to form a solution. Example: salt water. The salt (solute) is added to the water (solvent) and mixed until it dissolves and you are left with salt water (solution)
What makes water such a useful solvent?
Its polarity.
What is the difference between hydrophilic and hydrophobic?
Hydrophobic – water hating, repels water
Hydrophilic – water loving, attaches to water