exam 2 Revision Flashcards
How do covalent molecules dissolve in water? what are the bonds that form between molecules? draw diagrams
Only polar molecules dissolve in water but do not fully dissociate, their partially charged regions form either hydrogen bonds or dipole-dipole bonds with the water molecules.
How do ionic molecules dissolve in water? what are the bonds that form between molecules? draw diagrams
when ionic compounds dissolve, they break apart into individual ions that are stabilized by ion-dipole interactions with water, allowing them to stay dissolved and move freely in solution.
Why does water have a high specific heat capacity?
water has such a high specific heat capacity due to the strong hydrogen bonding between water molecules, These bonds require a lot more energy to break which allows it to absorb more heat without a significant rise in temperature.
Why does water have a high latent heat of vapourisation and fusion?
due to the strong hydrogen bonds between molecules, which require substantial energy to overcome.
explain why water expands once frozen.
When water turns to ice, its molecules arrange in a way that allows for the maximum number of hydrogen bonds to form (4) resulting in a more spread out structure then when the water is in liquid for thus the expansion.
What is the formula for latent heat of fusion/vaporization
Q(kj)= n x L or V
What is the bronsted- Lowery definition of acids and bases?
Acids are proton donors
Bases are proton acceptors
how do you identify conjugate acid base pairs
When an acid donates one proton, it forms a conjugate base.
When a base accepts a proton it forms a conjugate acid.
What is the relation between pH, [H3O+ ],[OH- ]
The formulas allow them to interchange between them.
what happens between reactions with acids and bases?
the acid donates protons to the base forming a conjugate base and a conjugate acid.
What are the products when an acid is mixed with a metal hydroxide?
It will form a salt and water
What are the products when an acid is mixed with a metal carbonate?
It will form a salt, water and carbon dioxide.
What are the products when an acid is mixed with a metal?
A salt and hydrogen gas will form.
What are the products when a base is mixed with water?
When a base is mixed with water, it typically produces hydroxide ions and a corresponding cation. Strong bases dissociate completely, while weak bases partially dissociate, establishing an equilibrium with water
Define and list the properties of weak VS strong acids/bases
strong- fully dissociate and reaction goes to completion.
weak- don’t fully dissociate and you have to use the both ways sign in the equations.
Define and list the properties of concentrated VS dilute acids/bases
Concentrated Acid/Base: A solution with a high amount of acid or base dissolved in a relatively small amount of water.
Dilute Acid/Base: A solution with a low amount of acid or base dissolved in a relatively large amount of water.
Concentrated acids and bases are more reactive, corrosive, conductive, and dense, with extreme pH values.
Dilute acids and bases are milder, less corrosive, less conductive, and have moderate pH values, making them safer for handling.
Define and list the properties of weak VS concentrated acids/bases.
A strong acid donates a proton more readily than a weak acid
A strong base accepts a proton more readily than a weak base.
Define and list the properties of Diprotic/Triprotic acids
Diprotic Acid: An acid that can donate two protons
Triprotic Acid: An acid that can donate three protons
Define and list the properties of Amphiprotic substances
A substance that can either donate or accept a proton in a chemical reaction.
How do you show - reactions showing gradual ionization of polyprotic acids in water
Multiple ionization equations.
How do you predict whether a reaction will occur by using the electrochemical series?
The backwards Z method, on the left going up is the weakest to strongest oxidizing agent and going down on the right it is weak to strongest reducing agent. The one on the left must be higher than the one on the right.
How do you write overall and half equations?
Separate the oxidizing agents and reducing and balance them separately and then out them together making sure there is the same charge on both sides- sometimes you have to multiply one of the half equations.
What does KOHES stand for?
Key elements
Oxygen by H2O
Hydrogens +
Electrons
States
What do you need to remember to add when drawing galvanic cells?
half cells, salt bridge/Ion movement, labelling, direction of electrons, anode, cathode,
What is the difference between saturated, unsaturated and supersaturated?
A saturated solution contains the maximum amount.
An unsaturated solution contains less solute than the maximum amount.
A supersaturated solution contains more solute
How do you find the concentration in g/l, mol/L, m/v% etc. ppm and ppb?
grams over liters
moles over liters
grams over ml
mg over kg
ug over kg
OR
same over same x 1 mil (or 1 bil)
how do you convert between kPa and atm?
to find kPa with atms- have the amount of atm over 0.987
atms from kPa- amount of kPa given over 100
What does end point and equivalence point mean?
equivalence point- when the acid has completely reacted with the base.
End point is when the indicator changes colour.
how do you rinse each piece of equipment?
Burette- solution
Pipette- solution
conical flask- water
volumetric flask- water
what is gravimetric analysis?
- form a precipitate
- filter and wash to rid of any impurities
- dry- in oven until it is dry
- weigh
- continue steps 3 & 4 until the substance doesnt change in weight at least 3 times.
What are the basic principles behind UV-Vi’s spectroscopy?
UV-Vis spectroscopy is a technique used to analyze the absorption of ultraviolet and visible light by molecules.
How do you construct calibration curves and interpret them?
You perform tests with known concentrations, and you plot the absorption on the Y and the M on the X. you plot the points, join them and then you are able to predict concentrations when you know the absorption of your sample.
How do you identify the limiting reagent and use stoichiometry to find amounts of products/reactants?
you find how much of each will produce the amount of product you need, whichever produces less is limiting.
What is the IV and the DV
IV-Changing variable
DV-Measured variable
What is validity?
validity in science guarantees that experiments, tests, and studies are designed and conducted in such a way that their results are accurate and truly reflect the phenomena being investigated.
What is accuracy?
accuracy in science ensures that the measurements and results obtained in experiments are close to the true or accepted values
What is precision?
Precision in science refers to the consistency and repeatability of results.
