Chem - Solutions - Unit Test

a homogenous mixture of two or more substances in a single phase; if one substance is a solid, it must be soluble in the liquid

solution

the dissolving medium

solvent

in an aqueous solution, what is the solvent

water

the substance dissolved

solute

in a salt water solution, what is the solute

salt

when both substances are the same phase, the volume of the solvent is _________ than the volume of the solute

greater

what are three factors than affect the rate of dissolution (solid solute)?

increasing the surface area of the solute

agitating a solutiion

heating the solvent

the dissolution process occurs at the ____ of the solute so if more surface is exposed, the solute will dissolve ______

surface, quicker

the concentration of the dissolved solute is very close to the solute surface. By ____ the mixture, the solute particles are dispersed and are able to contact ________

stirring, “fresh” solvent particles

as temperature increases, the rate of dissolving____

increases

increasing the KE (motion) of the molecules is similar to _____ the solution (except gas)

mixing

the quantity of solute that can be added to a quantity of solvent to make a saturated solution at a given temperature and pressure

solubility

the solvent is able to dissolve more solute particles

unsaturated

the solution holds as many solute particles that it can possibly hold. any more solute will sink as precipitate

saturated

in what type of solution is there an equilibrium between dissolved particles of solute and solid particles of solute

a saturated solution

rate of dissolving = rate of _______

crystalization

when does a supersaturated solution occur?

when a solution holds more solute than what “should be” possible

polar ____ dissolve in polar solvents

solutes

why does the polarity of water make It an ideal solvent for polar or ionic solutes?

water molecules force themselves between ions in an ionic solid causing the ions to separate and “dissolve”

why will water not dissolve non polar substances?

the water molecules are more attracted to each other (polarity) than the non polar substance (oil floats on water)

nonpolar solutes dissolove in _______

nonpolar solvents

what is an example of two nonpolar substances dissolving?

nail polish - made of acetone, which basically dissolves the enamel to remove it

what is the formula for molarity (M)?

= (moles of solute/liters of solution)

what is the formula for parts per million (ppm)?

= (grams of solute)/(grams of solution) x 1,000,000

what is the formula for percent by mass?

= (grams of solute)/(grams of solution) x100

what is the formula for percent by volume?

= (mL of solute)/(mL of solution) x100

what is the most commonly used unit of concentration in the lab?

Molarity

solve: what is the molarity of a solution if it contains 2.0 moles of NaCl in 250mL solution?

1. convert mL to L

   1. (2 moles)/(.250 L) = 8M

how can a weaker concentration (lower molarity) be made?

by diluting a more concentrated solution (higher molarity)

define: used to determine amounts of dissolved ions in drinking water, also used to measure the concentration of particles in the air

parts per million (ppm)

why is salt added to the roads in winter?

to decrease the freezing point of water so there is less ice on the roads

the term “colligative properties” refers to the effect of solute particles on the ___________ of the _________

behavior, solution

the properties of the solute don’t matter, only the ________ of _________

number, particles

what do covalent compounds do when dissolved in water?

stay together, yielding one particle per mole

what do ionic compounds do when dissolved in water?

dissociate into the number of ions in the formula

ask McCarthy more about concept above

the ______ particles dissolved in water, the ______ the boiling point and the _______ the freezing point

more, higher, lower

review word problems on blue and yellow sheets