U4 Flashcards
What is a solute, solvent, and solution?
Solute - What is dissolved (the substance of less quantity)
Solvent - What is doing the dissolving (substance of greater quantity)
Solution - the solute dissolved in the solvent. Homogenous.
Homogeneous vs hetergeneous mixture
Homo - Mixture of 2 or more substances. Fully mixed in any state.
Hetero - Obvious seperation in the mixture (i.e. oil and vinegar).
How do pure substances differ from solutions?
Pure substances have fixed composition (i.e. water is always H2O). Solutions are variable, different ratios.
What is concentration?
The solute to solvent or solution ratio
Concentrated vs dilute solution
Concentrated - high solute to solution ratio
Dilute - low solute to solution ratio
What is an aqueous solution (aq)?
A solution where water is the solvent
What is each type of solution (state in state), give an example of each
Solid in solid - Alloys
Solid in liquid - Sea water
Solid in gas - moth balls
Liquid in solid - Amalgam of mercury in silver
Liquid in liquid - Antifreeze in water
Liquid in gas - Water vapour
Gas in liquid - Carbonated beverages
Gas in gas - Natural gas or air
Gas in solid - !Very rare!
What affects the dissolving process?
Temperature - Hotter is faster for solid solutes (more kinetic energy)
Agitation - Stirring brings fresh solvent in contact with undissolved solid
Surface area - Smaller particle increases rate of dissolving
Why do some solutes dissolve but others don’t in certain solvents?
Attraction between solvent particles, solute particles (both need energy), and the attraction between solute and solvent particles (releases energy).
Strongly, slightly vs not polar
Strong - large electronegativity differences, assymetrical (forms ions in water)
Slight - Minor electronegativity differences, some assymetry (dissolves, but no ions)
Not - None or little electronegativity differences, symmetry (does not dissolve)
How to write a dissociation equation? What molecules can dissocosiate?
Only ionic compounds
Solid compound written on left
Water not included in equation
Eg.
K3PO4 (s) –> 3K+ + PO4-3
Define miscible and immiscible
Molecular compounds can vary in how easily they dissolve in water - miscible
Oil doesnt dissolve in water - immiscible
What does like dissolved like mean?
Polar solvents will dissolve polar solutes
Non-polar solvents will dosiolve polar solutes
They will not dissolve eachother
Define solubility
The quantity of a solute that can dissolve in a given quantity of solvent at a given temperature
How does ion charge and size affect solubility?
Ion charge and size. A small size is more insoluble because they are held tighter together. A large charge is more insoluble because it hold ions together.
How does temperature affect the solubility of liquids, solids, and gasses.
S - Hotter = more soluble
L - No effect
G - Hotter = less soluble
How does pressure affect solubility of liquids, solids, and gasses.
S & L - No effect
G - More pressure = more soluble
What are the degrees of saturation?
Saturated - Maximum amount of solute in a solution at a given temp
Unsaturdated - Less than maximum amount of solute in a solution at a given temp.
Supersaturated - Higher than the maximum amount of solute in a solution at a given temp and pressure.
- Done by heating a solution, saturating it, and slowly cooling it
Equation triangle for amount cocentration
mol (solute)
__________________________________
C (mol/L) | volume of solution (L)
C = n/V
When is volume/volume % concentration used? What is the triangle?
Used in liquid in liquid solution. Expressed as %. Same units on top and bottom.
v (solute) x 100
____________________
c(v/v) | v (solution)
When is mass/volume % concentration used? What is the triangle?
Used in solid in liquid solution. Expressed as %. Expressed as g and mL.
g (solute) x 100
___________________
c(m/v) | v (solution)
When is mass/mass % concentration used? What is the triangle?
Used in solid in solid solution. Expressed as %. Units must be the same on top and bottom.
m (solute) x 100
_______________________
c(m/m) | m (solution)
How to find ppm, ppb, and ppt?
Multiply % concentration by 10^6 (ppm), 10^9 (ppb), or 10^12 (ppt)
What is the equation for dilution?
c1V1 = c2V2
How to write net ionic equation?
Split the reaction into their ions on both sides excluding the precipitate
Cross out spectator ions on both sides (the ions that form aq compound)
Eg.
AgNO3 (aq) + NaCl (aq) –> NaNO3 (aq) + AgCl (s)
Ag+(aq) + NO3-(aq) + Na+(aq) + Cl-(aq) –> AgCl (s) + Na+(aq) + NO3-(aq)
Ag+(aq) + Cl(aq) –> AgCl(s)
How do you conduct sequential chemical analysis?
(reverse words cations and anions when working with anions)
1.Locate the possible cations on the solubility table.
2.Determine which anions precipitate the possible cations.
3.Plan a sequence of precipitation reactions that uses anions to precipitate a single cation at a time.
4.Use filtration between steps to remove cation precipitates that might interfere with subsequent additions of anions.
Summarize the Arrhenius Theory and it’s limitations
Summary:
Acids ionize to increase H+ concentration in a solution
Bases dissociate in increase OH- concentration in a solution
A neutralization reaction involves the reaction of a hydrogen ion with a hydroxide ion to produce water
Limitations:
Acids in water form hydronium, not hydrogen
Carbonate ions and ammonia are also basic
Limits reactions to water
IGNORE THIS CARD
Summarize the Bronsted-Lowry theory
Acids donate a proton, bases accept a proton.
Some compounds can act as both acid and base, such as water (amphiprotic).
What makes an acid strong? What are the 6 strong acids?
What makes a base strong? What are the strong bases?
Higher the concentration of hydrogen, the stronger the acid is.
HCl, HBr, HClO4, H2SO4, HNO3, HI
Higher the concentration of hydroxide, the stronger the base is.
Group 1 metals, group 2 metal below Be
How to find the amount of hydronium ions in water
How to find pH given the hydronium ions?
1 x 10^-pH
-log[H3O+]
How to find the pH of a solution after mixing an acid and a base?
!Balanced chemical equation
!Calculate moles of each reactant
!Determine which one is in excess and calculate the excess
!Find the new final concentration (remember to include the TOTAL volume)
!Calculate the pH
Define: Titrations, Titrant, Analyte, Burette, Equivalence point, Endpoint, Acid-Base Indicators
Titrations: A method to find the concentration of a substance using a solution of known concentration.
Titrant: A solution of known concentration used in titrations.
Analyte: The substance whose concentration is being measured.
Burette: A long tube used for delivering titrant with precision.
Equivalence Point: The point when the titrant completely reacts with the analyte.
Endpoint: The point where the indicator changes color, signaling the end of the titration.
Acid-Base Indicators: Substances that change color in response to changes in pH.
What are physical, biological and chemical contaminants?
P - Large bits that make water visibly dirtier
B - Harmful germs, viruses, bacteria
C - Caused by chemicals, poisonous, radioactive, etc.
What is a leachate?
A leachate causes pollution in water. It forms when liquid travels through a solid and takes some of the solid’s components with it.
What does maximum acceptable concentration mean?
The amount concentration established for certain substances that is deemed acceptable. MAC.
Soft vs Hard water. How to soften? Why is hard water worse?
Hard water contains more calcium and magnesium ions.
It is usually softened in the treatment process by adding a base to it.
Hard water can cause hard mineral build ups which clog things.
