mistakes

why does fermentation need to happen in the absence of air? (2)

• to prevent oxygen reacting with the ethanol

• to produce ethanoic acid

define concordant results

results within +-0.2cm3

why is the OH- ion a proton acceptor in this equation? (2)

• the H+ is a proton

• the OH- ion reacts with the H+ ion to form water

state the appearance of copper on the electrode

pink-brown solid

half equation for formation of oxygen at the cathode (aqueous electrolysis)

2H₂O —> O₂ + 4H⁺ + 4e⁺

catalyst to increase the rate of ester formation

sulphuric acid

how would you know that an ester has formed?

sweet fruity smell

Mr of H2

2

what shielding does fluorine have compared to chlorine

less shielding from the nucleus

draw the structural formula of a compound with the molecular formula C2H4O2

CH3COOH

in an ester what does carboxylic acid become?

-anoate

in an ester what does an alcohol become

-yl

combustion of ethanol, explain why the students value was lower than expected (3)

thermal energy lost to the surroundings

incomplete combustion of ethanol

ethanol evaporates/impure