chem unit 12
Terms in this set (48)
henry's law. equation and what are you solving for?
S1/p1=S2/Ps solubility and pressure
moles of solute/liters of solution
moles of solute/kilograms of solvent
what types of substances can dissolve in water?
what types of substances cannot be dissolved in water?
describe the process of solvation?
an ionic compound dissolves and dissociates into ions and are surrounded by water molecules
What are three ways in which to increase the rate at which a substance dissolves?
heat, stirring, increase surface area (smaller particles)
how can you increase the amount of solute which will dissolve?
What are the units for solubility?
describe the method for making a supersaturated solution
add more solute to the solvent than it can contain, then heat it up then cool it down so it will crystalize
how does temperature affect the solubility of solids? gasses?
temp increase makes solids more soluble (increases) and gasses less soluble (decreases)
how does pressure affect the solubility of solids? gasses?
pressure does not affect solids but makes gasses more soluble
what is the difference between a dilute and concentrated solution?
Dilute- solution with a small amount of solute compared to the amount of solvent. Concentrated- solution that has a lot of solute
What are three types of laboratory equipment that are used to make dilutions?
graduated cylinder, burette, volumetric flask
What does salt do to the vapor pressure of water?
decreases vapor pressure
what does salt do to the boiling point of water?
raises the boiling point
what does salt do to the freezing point of water?
how does salt change the boiling point and vapor pressure of water?
it holds the water molecules together so that it is harder for them to become a gas
how does salt change the freezing point of water?
it disrupts the crystal lattice structure
which solutions make the lowest freezing points and highest boiling points?
the ones that make the most particles
what tools can be used to measure the pH of a solution?
litmus paper, pH paper, indicator solutions, pH meter
why are acid/base reactions referred to as a neutralization reaction?
because the salt and water products that they produce are perfectly neutral
what is the significance of the equivalence point of a titration?
it is when the moles of H+ ions equal the moles of OH- ions. When they neutralize each other
how are the solutions used in a titration?
specific volume of solution A is added, one solution is a known concentration, the other is not. Add solution a by drop until solution B changes color
what determines whether or not a substance will dissolve in another substance?
strength of bonds vs attractive forces
the amount of solute that can be dissolved in a specific volume of solvent specific for temp and pressure
what two things can affect solubility?
temperature and pressure
the quantity of solute present in a given amount of a solvent
the molar concentration of a solute in a solution. the moles of solute present in a certain volume of solution
diluting a solution does what to the number of moles of solute per unit of volume? what about the total number of moles over all?
reduces the number of moles, total number of moles does not change
what equation is used for dilutions?
stock solution: a solution with a known concentration
how are dilutions prepared in the laboratory?
measure out volume of the stock solution using a graduated cylinder or burette. put in volumetric flask and fill with water up to the line
produce H+ ions. pH lower than 7
produce OH- ions. pH above 7
the addition of an acid to a base to produce a salt and water
when the # of moles of H+ ions equals the moles of OH- ions
the process of adding a solution with a known concentration to an unknown concentration to calculate the concentration of the unknown solution
the point where the indicator changes color
how to calculate the unknown concentration of solution using a titration
1.) balanced chemical equation
2.) known molarity and volume find the moles
3.) use stoic to find out the moles of the unknown
4.) unknown molarity
any property which depends on the # of solute particles and their identity
3 important colligative properties
freezing point depressing, vapor pressure lowering, boiling point elevation
vapor pressure lowering
adding a nonvolatile solute to a liquid will lower that liquid's VP by attracting the solute and making it more difficult for H2O to vaporize
boiling point elevation
adding solute will raise boiling point of the solvent
freezing point depression
a solute will lower the FP of a solvent by slowing down the formation of bonds. disruption of the crystal lattice structure
for all three colligative properties:
the magnitude of the change of the property is proportional to the # of soluble particles dissolved in the solvent
substance being dissolved
substance doing the dissolving