Sac 1 semester 2 Flashcards
what are the properties of water? justify them in relation to polarity.
Water has high heat capacity-
Water has high heat of vaporization.
Water is less dense as a solid than as a liquid - the molecules are arranged and more spread out than they are in liquid.
all the rest relate to how Water has strong hydrogen bonds between its molecules
Hydrogen bonds are stronger than other intermolecular forces.
list and explain four properties of water and how these may be important for sustaining life on earth
Less dense in solid than liquid- it keeps ponds, lakes, and oceans from freezing solid and allows life to continue to thrive under the icy surface.
High SHC-helps maintain cellular temperature and supports biological processes that are sensitive to temperature changes.
universal solvent-helps cells transport and use substances like oxygen or nutrients
cohesion and adhesion-moving water through out plants and so on, using a pull system.
what is specific heat capacity?
Energy needed to change the temp of 1g of substance by 1oC
why does water have a higher SHC than any other substances?
Due to hydrogen bonding, where the temperature equals average kinetic energy of particles. The energy goes into speeding up the molecules which will cause the temperature to increase. when the energy is given to water it is absorbed by the hydrogen bonds that exist between the water molecules, this energy goes towards breaking the hydrogen bonds first, not into speeding up the water molecules therefore more energy is needed to heat water up.
what are the calculations involving SHC
Q=mcAT
what is latent heat?
Energy needed to change state of 1 mol of substance from solid to liquid (or liquid to solid). also Liquid to gas and vice versa
why does temperature not change during melting/evaporation in terms of the bonding and kinetic energy of particles?
The temp remains constant as the substance is turning from solid to liquid, liquid to gas and vice versa. the energy involved during this time is not being used to break bonds therefore there is no increase in kinetic energies of the particles.
why is latent heat higher for water
Hydrogen bonds are stronger than other intermolecular forces so more energy is used up to break these H bonds compared to other weaker intermolecular bonds that exist between most other molecules.
what are the calculations involving latent heat?
q=nxLv or Lf
Bronsted-Lowery definition of acids and bases
Acids are proton (π»^+) donours
Bases are proton acceptors
Acid + water
Base + water
products:
The reactions of acids or bases with water are called ionisation reactions because ions are produced.
e.g base- ππ»_3 (ππ)+π»_2 π(π)βππ»_4^+ (ππ)+ππ»^β (ππ)
acid-π»πΆπ(ππ)+π»_2 π(π)βπΆπ^β (ππ)+π»_3 π^+ (ππ)
what are the products of a Acid + metal carbonate reaction?
Acid + metal carbonateβ Salt+ water+CO2
what are the products of a Acid + metal hydroxide reaction?
Acid+ Metal Hydroxideβ salt + water
what are the products of a Acid + metal reaction?
acid + metalβ Salt + h2
what are the 3 formulas involving PH
PH=log10[H3O+], [H3O+][OH-]=10-14, [H3O+]=10PH
what is the difference between a strong/weak acid/base?
Strong acids/ bases fully dissociate in water the reaction goes to completion whereas weak acids/ bases donβt fully dissociate into ions when they react with water leaving the reaction incomplete.
A strong acid donates a proton more readily than a weak acid and a strong base accepts a proton more readily than a weak base
what is the difference between a diluted or concentrated acid/base?
A diluted acid/base is when there isnβt as much of the substance compared to the rest of the volume, A concentrated acid/base is when that is a lot of the substance compared to the rest of the volume.
what is calcification and how is it being affected by increasing ocean acidity?
The formation of calcium carbonate is called calcification, and this is used by many marine animals to form shells to protect themselves. However, calcification has been had increased worry as ocean acidity increases, in which causes the shells to react with the increased H3O+ particles in the water which results in the shells breaking down and becoming thinner and more marine animals canβt produce their shell to its full potential during embryonic stages and development as there is not enough carbonate in the water.
What does an oil rig cat stand for?
Anode
Oxidation
Is
loss (e-)
Reduction
Is
Gain (e-)
Cathode
how do you identify if its oxidation occurring? then what about reduction?
Oxidation is the loss of electrons and the charge goes up
reduction is the gain of electrons and the charge goes down.
how do you determine the oxidant/reductant?
The oxidant is the molecule thatβs going under reduction and the reductant is the particle going through oxidation
what is a half equation?
Even though reduction cannot occur without oxidation at the same time half equations are written to emphasise which is gaining and which is losing electrons
how do you turn 2 half equations into full ones?
To turn to half equations into a full equation you must make sure that the charge on both reactions equals the same so sometimes you have to times the entire equation before you put them together.
what are the keys of chemistry (kohes)
Key elements
Oxygen by adding H2O
Hydrogen by adding H+
Electrons
Sates
how do you use the electrochemical series to predict if a reaction will occur?
For this to work there must be a backward Z to work, the oxidant must always be higher than the reductant
what do you need to include in diagrams of galvanic cells?
in diagrams of galvanic cells you need to label the cathode and anode, which direction the electrons are going, the electrolytes and electrodes, half equations, the full equation and which is going under reduction and oxidation as well as labelling the salt bridge and which way the positive cations go and where the negative anions go
