The Randos
Water is called the "universal solvent" and it often has ions dissolved that help it conduct electricity.
Is PURE water (no ions) a good conductor of electricity?
What is...
NO!
(because there are no ions or electrolytes)
Does stirring increase or decrease the rate (how fast) of something dissolving?
What is...
Increase
What term means the substance that is dissolved in a solution?
What is...
Solute
If water boils at 100º C, and a 12M baking soda solution has a boiling point of 112ºC...what is the boiling point of a 12M salt solution?
What is...
112ºC
**Why? colligative properties
What was the main chemical we used to look at factors affecting the rate at which something dissolves?
What is...
Salt
What do Colligative properties depend on?
(Identity (What type) or Amount (How much))
What is...
Amount
**The two we talked about are freezing point depression and boiling point elevation**
What are the 3 factors affecting the RATE (how fast) at which something dissolves?
What is:
Stirring
Surface Area
Temperature
If electrolytes and non-electrolytes are dissolved in two different beakers, which one should conduct electricity?
What is...
The one containing the electrolytes.
what is the molarity of a solution that has 0.87 moles of NaCl dissolved in 87 Liters of water?
What is...
0.01M NaCl
What was the purpose of the mortar and pestle in our lab?
What is...
It was used to crush the large rock salt into a fine powder.
There were 4 ways to measure concentration. We looked at 2. Which one is defined as (think about the formula) moles of a substance divided by the number of liters of the solution?
What is...
molarity
**Remember that molarity MUST use moles and liters...not milliliters and/or grams**
As the pressure above a liquid decreases, what happens to the solubility of gases?
(increase/decrease)
What is...
The solubility will DECREASE
What term describes the "amount of solute" in a "given amount of solvent?"
(Ex. molarity, molality, percent by mass are all ways to calculate the ____________)
what is...
concentration
Dilutions:
200mL of a 13.5M solution are diluted with 500mL of water to give a new volume of 700mL, what is the new concentration of the solution?
What is...
3.86M
True/False:
A saturated solution will have excess solid remaining at the bottom of the container.
What is...
True
What are the 3 main ions responsible for cellular communication (muscular/nervous systems)?
What are...
K+, Cl-, and Na+
As Temperature increases, how is the solubility of gases affected?
Solubility of gases decreases
What kind of solution has more than the max amount of solute dissolved for a given temperature?
(saturated, unsaturated, supersaturated)
What is...
Supersaturated
**Unsaturated will have less and will be able to dissolve more at a given temperature.
More Molarity:
If you want to create a 2.3 Molar solution using 10.4 grams of NaCl, how many mL of water would you need?
What is...
77.4 mL
Describe our method for stirring the solution in our lab.
What is...
We inverted the test tube.
Explain:
What is the MAJOR difference between dissolving ionic solutes/molecular solutes in water?
(video we watched in class)
Ionic compounds will dissolve into individual ions. (The individual atoms will literally be pulled apart due to water's polar nature.) Molecular compounds will dissolve into individual molecules but will NOT break into the individual atoms that compose those molecules.
Using one of the 3 factors affecting how much will dissolve, explain why water and oil do NOT mix.
(think about the polarities)
Like dissolves like...
Water is polar. Oil is non-polar. Because the polarities are different, the compounds do not want to mix (and as a result are not miscible).
What is the difference between miscible and immiscible?
Miscible means two liquids that WILL dissolve in each other/mix with each other (vinegar and water).
Immiscible means two liquids that will NOT dissolve in each other/mix with each other (oil and water).
If we have 2L of a 3M NaOH solution, how many grams of NaOH are dissolved in the solution?
What is...
240 grams of NaOH
Describe how each of the following phase changes are affected (raised or lowered) when salt (or any solute really) is added to water. Hint: Think of the Colligative Properties.
Condensation, Vaporization, Melting, Freezing
What is...
Freezing and Melting point temperatures are both lowered. Condensation and Vaporization points are both raised.