Answer:
E = 8.5 * 10^6 V/m
Explanation:
In general we have the following relation between the Electric Field and the Elecric Potential:

Due to the vector nature of the electric filed, we can only know the mean Electric field E across the membrane, and take it out from the integral, that is:
E = (ΔV)/L
Where L is the thickness of the membrane and ΔV is the potential difference.
Therefore:
E = 8.53933*10^6 V/m
rounding to the first tenth:
E = 8.5 * 10^6 V/m
Density is defined as (mass) per unit (volume). So in order to calculate
the density of a glob of some substance, you pretty much have to measure
its mass and its volume.
Detailed Explanation:
1) Rusting of Iron
4Fe + 3O2 + 2H2O -> 2Fe2O32H2O
Reactants :-
Fe = 4
O = 3 * 2 + 2 = 8
H = 2 * 2 = 4
Products :-
Fe = 2 * 2 = 4
O = 2 * 3 + 2 = 8
H = 2 * 2 = 4
2) Fermentation of sucrose…
C12H22O11 + H2O -> 4C2H5OH + 4CO2
Reactants :-
C = 12
H = 22 + 2 = 24
O = 11 + 1 = 12
Products :-
C = 4 * 2 + 4 = 12
H = 4 * 5 + 4 = 24
O = 4 * 2 + 4 = 12
Looking closely at the way I have taken the total number of elements on the reactants and products side, you can solve the rest.
All the Best!
Gravity affet everything and it touches nothing.
Hope this helps!