Chemistry Extended Answer

bank for all types of questions asked in ER for WACE

What is the primary structure of a protein

primary structure of a protein is the sequence of α-amino acids.

α-amino acids are joined by peptide or amide bonds

What is the secondary structure of a protein

secondary structures result from hydrogen bonding between amide group hydrogen atoms and carbonyl group oxygen atoms.

secondary structures are either classified as α-helixes and/or β-pleated sheet.

α-helix is a secondary structure that results from hydrogen bonding between amide and carbonyl functional groups within a peptide chain

β-pleated sheet is a secondary structure resulting from hydrogen bonding between amide and carbonyl functional groups along adjacent polypeptide chain

what is the teritary structure of a protein

tertiary structure of a protein is a result of folding of the polypeptide chain/overall shape of the protein.

tertiary structure forms due to interactions between side chains of α-amino acids in the polypeptide

what are the different types of side chain interactions?

disulfide bridges

hydrogen bonding

dipole-dipole interactions

dispersion forces

ionic interactions

Use collision theory to explain how the presence of catalysts in production proccesses are viable.

Catalysts improve the viability of proccess by increasing reaction rates.

The catalyst provide an alternative reaction pathway with lower activation energy.

With a reduced activation energy, there will be a greater proportion of successful collisions occuring with sufficient energy, and thus a higher frequency of successful collisions

Use collision theory to explain how increasing the temperature of a system in production impacts yield

An increase in temperature increases the average kinetic energy of all particles.

There is an increase in the frequency of collisions in both forward and reverse reactions.

There is also an increase in the proportion of collisions that reach the activation energy in both forward and reverse reactions.

But as the proportion increase is greater for the [F/R] endothermic reaction, the equilibrium position shifts [L/R]

use collision theory to describe the effect of raising the total pressure on the yield

When pressure is increased, (the reactant and product) particles are forced closer together increasing rate (frequency) of collision.

therefore increases the rate of reaction of both the forward and reverse reactions. Ratio of gaseous particles of LHS to RHS as written is x:y.

The [r/f] reaction as written has a greater proportion of gas particles hence forward reaction proceeds faster than the reverse reaction until the equilibrium conditions are re-established.

This results in a greater proportion of [p/r] of the [r/f] reaction

use collision theory to describe the following conditions:
high temperature

catalyst

high temperature
high pressure

catalyst:

increases rate of reaction by providing an alternate pathway with a lower activation energy.

There will be an increased proportion of particles colliding with energy greater than activation energy, resulting in increased frequency of successful collisions

Temperature:
increased temperature increases the average kinetic energy of particles and they collide more frequently

increased proportion of collisions will have energy higher than the activation energy

greater proportion of collisions are successful

Pressure:
ncreased pressure reduces the space between reacting particles

particles collide more frequently

higher frequency of successful collisions

what are 3 conditions for a good primary standard?

relatively high molar mass

soluable in water

non-hygroscopic(tendancy to absorb with water)

justifications for choice of an indicator?

That a change in colour of the indicator (end point) indicates that the equivalence point has been reached.

The (appropriate) indicator changes colour in the range of the equivalence point.

____ is the only indicator that changes colour in the range of the equivalence point

Why is compound 1 soluble in water but compound 2 not?

compound ____ is soluble/insoluble

compound 1 is predominantly attracted via _______ forces. compound 2 is predominantly attracted via _______ forces.

For a compound to be soluble, the solute-solvent interactions must be greater than original solute-solute and solvent-solvent interactions

compound 1 and water _____ forces are not strong enough to overcome original solute-solute and solvent-solvent forces.

compound 2 and water _____ forces are strong enough to overcome original solute-solute and solvent-solvent forces.

hence, new bonds are formed between between compound 2 and water.

therefore, compound 1 will dissolve, and compound 2 will not.

why is compound 1 soluble in ethanol but not water

compound 1 predominantly has __ forces

water has hydrogen bonding, dipole-dipole and dispersion forces

ethanol has hydrogen bonding, dipole-dipole and dispersion forces

compound 1 can form dispersion forces with water and ethanol

however, compound 1 forms greater dispersion forces with ethanol rather than water

the energy released in the formation of hydrogen bonds, dipole-dipole and dispersion forces between ethanol and compound 1 are sufficient to overcome existing forces of attraction between compound 1 molecules and ethanol molecules

the energy released in the formation of hydrogen bonds, dipole-dipole and dispersion forces between water and compound 1 are insufficient to overcome existing forces of attraction between compound 1 molecules and water molecules

what is the production steps for producing biodiesel

1. filteration

2. remove water

3. Remove Free Fatty Acids(FFA) through esterification:

FFA + methanol =(eq, H2SO4)= FAME + H2O

4. trans-esterification:
   

TG + methanol =(NaOH)= 3FAME + glycerol

// FAME= Fatty Acid Methyl Ester, AKA biodiesel

What is PET (the polymer)

what is nylon 6,6 (the polymer)

what is the purpose of a salt bridge?
what is a type of salt used and which ions flow to which cell

To prevent the build of polarity on either side of the cell

KNO3; anion to anode and cation to cathode

what are the half equations for an ALKALINE cell

what are the half equations for a LECLANCHE(acidic/dry) cell

Explain everything about an alkaline fuel cell

anode = nickel, fueled by H2 gas

cathode = nickel oxide, fueled by O2 gas

Explain everything about an acidic fuel cell

anode = carbon-platinum, fueled by H2 gas

cathode = carbon-platinum, fueled by O2 gas

explain how in electrorefining, the cathode remains pure

The applied cell voltage is carefully controlled so that only Cu+ (aq) ions are able to be reduced

less reactive metals simply fall to the

bottom of the electolysis cell(anode sludge/slime) [e.g. gold]

Other cations unaffected and remain in

solution. [e.g. nickel]

electrolyte = CuSO4 and H2SO4

rust equations and anode/cathode

anode = iron and water meet

cathode = iron, water and air meet

eq1: anode

eq2: cathode

how to prevent rust?

galvanising - covering iron in another metal that is more likely to oxidise(like zinc) so work even if its scratched

DC current - connecting negative terminal to iron supplies it with electrons, meaning it does not have ability to oxidise(due to it being cathode), however another piece of iron or metal is needed to be connected to anode for it to be oxidised.

what is the overall equation for the process of fermentation being used to make ethanol
Glucose

sucrose

what are the basic reactions of acids, bases and metals

acid + metal

acid + base

acid + metal carbonate
metal + water

___/____ displacement

acid + metal = salt + h2

acid + base = salt + h2o

acid + metal carbonate = salt + co2 + h2o
metal + water = metal hydroxide + h2

___/____ displacement = halogen, metal