13.2, 15.1, 15.2, 16.1 Flashcards
evaporation
vaporization that occurs at the surface of a liquid that is not boiling
boiling
vaporization throughout the liquid when vapor pressure is equal to the outside pressure
boiling point
the temperature at which the vapor pressure of a liquid is just equal to the external pressure on the liquid
normal boiling point
the boiling point of a liquid at a pressure of 101.3 kPa or 1atm
solvation
a process that occurs when an ionic solute dissolves
what happens when things dissolve in a solution
solvent molecules surround the positive and negative ions
vapor pressure
a measure of the force exerted by a gas above a liquid in a sealed container
a dynamic equilibrium exists between the vapor and the liquid
surface tension
an inward force that tends to minimize the surface area of a liquid
it causes the surface to behave as if it were a thin skin
solution
a homogeneous mixture, consists of solutes dissolved in a solvent
solvent
the dissolving medium in a solution
solute
dissolved particles in a solution
soluble
tendency to dissolve in a specific amount of solvent at a specified temperature and presssure
insoluble
tendency not to dissolve
diple
a molecule that has two poles, or regions, with opposite charges
miscible
describes liquids that dissolve in one another in all proportions
immiscible
describes liquids that are insoluble in one another
example of immiscible
oil and water
saturated
maximum amount of solution
unsaturated
less than maximum amount of solution
supersaturated
more solute than it can hold at a given temperature
two biggest differences between a liquid and a gas
the particles are farther apart in a liquid
intermolecular forces important in a liquid, negligible in a gas
what happens to a liquid as it evaporates
average kinetic energy goes up, intermolecular forces are broken from the surface and some particles turn into a gas
what happens to the temperature of a liquid as it evaporates
it goes down
what affects the rate of evaporation? How and why?
heating speeds it up because the kinetic energy of the particles increases
in a closed container, what is going on between the liquid and the vapor?
vapor pressure increases until it reaches dynamic equilibrium
rate of evaporation = rate of condensation
the liquid partices at the surface vaporize and produce increased vapor pressure, so then they later condense and return to liquid state
how does an increase in the temperature of a contained liquid affect the kinetic energy? Vapor pressure?
it increases them both
can a boiling liquid ever be increased above the boiling point by adding more energy
no
how can water be made to boil above the normal boiling point
higher external pressure
what are the six phase changes and what phases do they convert between
sublimation - solid to gas deposition - gas to solid evaporation - liquid to gas condensation - gas to liquid freezing - liquid to solid melting - solid to liquid
what are the conditions of a polar bond
two different atoms
asymmetrical
what are the conditions for a non-polar molecule
2 same atoms
symmetry
how many bonding pairs of electrons are there in water
2
how many non-bonding pairs are there
2
what is the shape of water
bent
what is electronegativity
the ability of an atom to attract electrons when the atom is in a compound
which part of the periodic table are elements with the greatest electronegativities found?
top right
which elements do not have electronegativity values and why
noble gases
full
don’t bond
which element in water has the highest electronegativity
oxygen
which element in water has the lowest electronegativity
hydrogen
Which element in water pulls the electrons closer to it
oxygen
what is the charge on oxygen in water
slightly negative
what is the charge of hydrogen in water
slightly positive
Is water a polar molecule
yes
what is hydrogen bonding
positive attracts to negative of another
attractive forces in which a hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom
what are two consequences of hydrogen bonding in water
high surface tension
low vapor pressure
what does a surfactant do
interferes with hydrogen bonding and reduces surface tension
example of surfactant
detergent
bonds between water molecules are
hydrogen bonds
bonds between the H and O within a water molecule are
polar covalent bonds
Why does water have such a high boiling point compared to other compounds
hydrogen bonding causes high surface tension, particles can’t break up as easily
why does it take so much energy to melt ice
hydrogen bonding
how can the boiling point be adjusted or changed
increased pressure will increase boiling point
increased altitude will lower boiling point
why is ice less dense than water
hydrogen bonds hold water in open framework
what is a homogeneous solution
solution that is uniform in composition
can the solute be filtered out from the solvent in a homogeneous solution
no
what types of substances can be dissolved in each other
like
polar in polar
nonpolar in nonpolar
what solutes form an electrolyte when dissolved in water
ionic compounds
under what other conditions do ionic compounds conduct electricity
when they are molten and soluble
what solutes are most likely to dissolve in water
ionic and polar
what solutes form non-electrolytes when dissolved in water
molecular compounds
what type of solution can conduct electricity
electrolytes
what types of elements for electrolytes
ionic
are all molecular compounds non-electrolytes
no
what molecular compounds are electrolytes
acids
NH3
What is the difference between weak and strong electrolytes
strong electrolyte - strong electric current, dissociate into ions completely
weak electrolyte - weak electric current, few ions dissociate
vaporization
the conversion of a liquid to a gas or vapor
Why might an ionic compound not dissolve in water
not soluble - attractions are stronger
how could you tell whether a compound would dissolve in water or not
solubility table
what affects the rate of dissolving
stirring
temperature
surface area
what is the expression for solubility
the number of grams of solute per 100g of solvent at a certain temperature
what affects the solubility of a solute and how?
temperature, pressure, nature of solvent (polar, nonpolar)
temp goes up, solubility goes up
what affects the solubility of a gas
temperature and pressure
how could you tell whether a solution was supersaturated
drop solute in and if it crystallizes is supersaturated
