Honors Chemistry: Unit 11 - Solutions

What is the molarity of a solution that contains 0.630 mol HCl in 4.19 L solution?

0.150 M

What equation would you use, plugging in the numbers, to solve: "A student wants to dilute a concentrated solution of KOH. He originally has a 540 mL of 3.2 M solution. He ADDS 320 mL of water to the solution. What is the new molarity of the solution?"

3.2M(0.540L)=x(0.860)

What is the VISIBLE difference between a saturated and unsaturated solution?

A saturated solution would have solid at the bottom.

What is the best way to determine if an aqeuous solution of sodium acetate is supersaturated?

Add a crystal of the original solute to the solution to see if more crystals form than were added.

How do you make a solution change from saturated to unsaturated?

Add more solvent (water) until the solid dissolves

How would decreasing the temperature of the solvent affect the solubility?

Decreases the solubility. Lowering the temperature lowers the kinetic energy, meaning less contact and no IMF weakening.

The scattering beam of light is referred to as the _______________________________.

Tyndall Effect

If sugar is dissolved in water, what is the solvent?

Water

suspension:

a heterogeneous mixture where the particles in a solvent are so large that they settle out unless the mixture is constantly stirred. EX: mud and water

A spectator ion is NOT shown in.....

a net ionic equation

Good Solvent:

because of its polarity, generally POLAR AND IONIC substances will dissolve in water while nonpolar substances won't

Agitation:

causes COLLISIONS between solute and solvent. EX: shaking your pre-workout

Temperature:

changes the kinetic energy of the particles in a solution

Water has the highest ______________ of the non-metallic liquids.

cohesion

Weak electrolytes are a contrast to a ____________________ where NONE of the dissolved compound exists as ions.

nonelectrolyte

Neutral Substance:

pH=7.0

WATER IS _____________

polar

"Crystals added to a flask containing CsCl settle to the bottom of the flask" is an example of what kind of solution?

saturated

Aqueous Solution:

solution in which water is the solvent

saturated solution:

solution that contains the MAXIMUM amount of dissolved solute

The abnormal physical properties of water can be attributed to....

strong hydrogen-bonding intermolecular forces

Solute:

substance dissolved, usually of lesser quantity

"More crystals than were added appear at the bottom of a flask containing CsCl" is an example of what kind of solution?

supersaturated

Water has a high ______________ ______________ because it's cohesive.

surface tension

Particles from a ________________ can be filtered with using filter paper.

suspension

Order solution, suspension, and colloids based on their particles size (big to small).

suspension, colloids, solution

effervescence:

the BUBBLING of a solution due to the escape of the gas solute

Brownian Motion:

the erratic random movement of microscopic particles in a fluid, as a result of continuous bombardment from molecules of the surrounding medium

How does the Tyndall effect work?

the individual suspended particles scatter and reflect light, making the beam visible

Molarity or M (mol/L):

the number of moles of solute in one liter of solution (M=mol/L)

solution equilibrium

the rate of crystallization and dissociation are equal. the same # of molecules going into the solution are coming out.

Tyndall Effect:

the scattering of a light beam as it passes through a COLLOID

dissociation:

the separation of IONS that occurs when an ionic compound dissolves. EX: NaCl -> Na + Cl

Does adding water to your tea when it is too concentrated change the number of moles of solute you have in the solution?

this DOES NOT change the number of moles

What do strong electrolytes mean regarding ions?

this means that ALL or ALMOST ALL of the dissolved compound is in the form of ions. EX: HCl

What do weak electrolytes mean regarding ions?

this means that ONLY A SMALL AMOUNT of the dissolved compound is in the form of ions EX: HF

"No visible solute appears at the bottom of the flask when adding CsCl crystals to a flask already containing CsCl" is an example of what kind of solution?

unsaturated

If the amount of solute present in a given solution is less than could be dissolved at a given temperature, then the solution is ________________________.

unsaturated

Which of the following would decrease the rate of dissolving an ionic compound in water?

use a single cube of solid without breaking it up

Because of the hydrogen bonds in water, molecules of water have a hard time escaping into the atmosphere as vapor. This accounts for water's LOW ____________________ __________________.

vapor pressure

Which device measures exactly one liter?

volumetric flask

If your tea is too concentrated, you'd add _________________.

water

BOILING POINT elevation:

when a solution has a higher boiling point than the original solvent did

immiscible:

liquid solutes and solvents that ARE NOT SOLUBLE in each other. EX: layers in italian dressing

miscible:

liquids that dissolve FREELY in one another in any proportion.

cohesive:

means that water sticks to ITSELF because of its polar nature

adhesive:

means that water sticks to OTHER SUBSTANCES that are hydrophilic or strongly attracted to water

colloids:

mixtures formed from particles that are sized between those in solutions and suspensions, particles small enough to be SUSPENDED throughout the solvent BY THE CONSTANT movement of the surrounding molecules (cloudy water).

a forced saturation is usually caused by an _______________ in temperature, thus WEAKENING the bonds or IMF within the solute

increase

An increase in temperature ___________ a solid's solubility in a liquid.

increases

Give the net ionic equation for the following reaction: BaCl2 + Na2SO4 -> BaSO4 + 2 NaCl

Ba+2 + SO4-2 -> BaSO4

TRUE OR FALSE: Viscosity usually increases with increasing temperature?

FALSE

How would crushing the solute into small pieces affect the solubility?

Increases solubility by further exposing the solute to the solvent.

How would shaking the solution affect the solubility?

Increases the solubility by increasing collisions

What equation would you use, without plugging in the numbers, to solve this problem?: "If the INITIAL concentration of a lithium carbonate solution is 2.5 M and you want to make 250 mL of a 0.42 M solution, how many liters of the original solution should you use?"

M1(V1)=M2(V2)

How would you make 1 M of NaOH?

Measure out a mole of NaOH (convert to grams....39.997g) and THEN proceed to add water until you reach the 1 liter mark.

What units are used to describe the solubility of a substance in a given soluton?

Molarity (mol/L) or amount of solute/amount of solvent

An ionic compound is dissolved in water. When tested for conductivity, the solution appeared to not conduct electricity. What is the reason for why this occurred?

Only a portion of the solute dissociated making it a weak electrolyte.

The expression "like dissolves like" refers to which property of molecules?

POLARITY

Which type of solution has achieved equilibrium, between solute and solvent, when the solute is still visible after stirring the solution?

SATURATED

What will happen to the ability of a gas to dissolve in a liquid if the temperature INCREASES? Why?

Solubility decreases because raising the temperature causes the gas to gain too much energy to remain in the solution.

A student observes crystals at the bottom of a flask that contains a solution of LiBr in water. What is the best way to determine whether the solution is saturated?

Stir it!

What does it mean for a solution to be in equilibrium?

The rate of dissolution is equal to the rate of crystallization.

unsaturated solution:

a solution that contains LESS SOLUTE than a saturated solution under the existing conditions

supersaturated solution:

a solution that contains MORE dissolved solute than a saturated solution contains under the same conditions.

surfactant:

a substance that REDUCES the surface tension of a liquid in which it is dissolved

Surface Area:

alters the exposure of the solute to the solvent... like breaking up a sugar cube in your tea

Polarity is related to _________________________________________. In a solution, polar molecules ____________________with non-polar molecules.

an uneven distribution of electron density in molecules; do not interact strongly

Strong Electrolytes:

any compound whose dilute aqueous solutions CONDUCT ELECTRICITY well

Weak Electrolytes:

any compound whose dilute aqueous solutions conduct electricity POORLY.

Why does ice float in water?

it is less dense than water due to its structure and increase in space between molecules and increase in hydrogen bonds

What is the amount of solute per given amount of solvent?

concentration

A decrease in temperature usually _________ the solubility of common salts in water.

decreases

A increase in temperature ____________ a gas' solubility in a liquid.

decreases

colligative properties:

depends on the CONCENTRATION of solute particles but not on the solute's identity.

Solvent:

dissolving medium

What are some examples of colligative properties?

freezing point depression and boiling point elevation

FREEZING POINT depression:

freezing point of a liquid (solvent) is lowered when another compound (solute) is added to form a solution

Colloids...

have the ability to scatter light

Solution:

homogeneous mixture of two or more substances in a single phase, may exist in any state