Module 1 Flashcards
What is a limiting reagent?
When there is a limited amount of one reactant ductort not being present in it’s exact stoichometicc when the limited reactant is used up, the reaction is complete.
How do you find the limiting reagent?
Calculate the amount in mols of each reactant consider the - stoichiometric ratio and whether One needs to be multiplied or divided.The laden value will be the limiting Reagan.
What makes water a good solvent
Polar-nature due to polar 0-h bonds
hydrogen bonding both within it’sself and with other substances.
What are the unique qualities of water.
Extremely high melting and boiling points.
Move dense in liquid form
What is the purpose of kc?
Describes the composition when it has reached equilibrium.
If k is large?
Equilibrium position has more products, so lies to theright.
What is the purpose of Q?
Describes the composition of a system at any point.
What does Le chatterers principle state.
In response to some change, the system will act to counteract the change and restore equilibrium.
What is the mol 1
Si unit for amount of substance 1 mol =6.022-1023
Concentration of products increases?
Q will be > k so the position ot e/quilibrium will move to the left.
If concentration at reactants increases
Quill be
Pressure increases by decreasing the volume.
Position of equilibrium will change to give a smaller number ot molecules (side with least number of gases molecules.)
Temperature is changed
The value of k will change, the systemwill no longer be at equilibrium., a shift will actor to restore equilibrium.
A catalyst is present
Catalysts don’t affect position of equilibrium but may increase time taken to reach equilibrium.
What is solubility.
Solubility refers to how much of a solid dissolves in a given volume of solvent, when ‘ the solution becomes saturated, equilibrium has been reached.
What is solubility product kip
Equilibrium formed between undissolved solid and dissociated ions -
When will a ppt form?
When Q is greater than K
What is the common ion effect?
Solubility of salt is reduced but solubility product doesn’t change.
What is a Lewis acid and base?
Acid= electron pair acceptor and bas = electron pair donor.
What are bransted lowly acids and bases?
Acid= proton donor and base =proton acceptan.
What is autoprolysis?
Water can act as either anacidorbase,
What is Ka and kb?
Measure ot acid or base strength,a greater number - greater dissociation.
Relationship between a conjugate acid base pair.
If one is strong the other is weak.
How do aqueous transition metal cations act as weak bases?
The cation pulls elections from away the o-ht bonds in water so thatHis released and reacts with a solvent water molecule to form h3ot..= complex ion.
What is a buffer solution?
A buffer solution contains comparable amounts at a conjugate acid base pain, which. Is able to resist a change in pit when significant amounts of hyelronium or hydroxide ions are added.
How is a buffer solution prepared?
Mixing a weak acid with the salt ef it’s conjugate base.or mixing weak acid with smaller amounts of strong base.
What is buffering capacity?
Buffer capacity is the amount of acid or base that can be added without changing the plot by more than one pl unit
What is happening in the buffer region.?
Added oh- converts acidinto conjugate base, creating a buffer solution.
What happens at the equivalence point?
Acid is completely neutralised by the added base, resulting Ina salt.
What happens at the half equivalence point?
Ht is consumed by olf- added, forming H2O
Equivalence point cf strong acid titration.
Ht is completely neutralised by oh-so plt=7
What are diprotocacids?
An add that has 2 protons to donate.
Amino acids?
All amino acids have both a weak acid and weak base within the same molecule.
What are zwitterions?
Neutral amino acids. They contain both a negative and positive charge but the overall molecule is neutral. They act like ionic salts. -
How do basic and acidic conditions affect zwitterions?
Under very and conditions they will be protonated. Under very conditions they will be deprotonated
What are the issues with the oxidants used in chemistry
They are toxic, require low pH solutions and are unsekectivr.
