B is the.answer for this problem
Answer:
The standard cell potential of the reaction is 0.78 Volts.
Explanation:

Reduction at cathode :
Reduction potential of
to Cu=
Oxidation at anode:

Reduction potential of
to Fe=
To calculate the
of the reaction, we use the equation:

Putting values in above equation, we get:

The standard cell potential of the reaction is 0.78 Volts.
Answer:
3 will be the correct coefficient of CaBr2
Explanation:
In balancing a chemical equation, numbers should be assigned to both reactants and products as a numerical coefficients until all atoms of elements in both sides of the equation count equal.
The balanced equation of the reaction will be:
3CaSO4 + 2AlBr3 ==> 3CaBr2 + Al2(SO4)3
Looking at the unbalanced equation in the question, in the product Al2(SO4)3 there are 3 SO4 group. This will warrant putting 3 behind CaSO4 in order to balance the atoms of SO4 group. That operation will automatically put the number of Ca atoms in CaSO4 to be 3 therefore making CaBr2 to have 3 coefficient as in the balanced equation. This is to balance the number of Ca atoms in both sides to be 3.
To get the molecular formula we use the individual atomic masses of the atoms making the molecule. Hence, to get the factor by which the empirical formula is multiplied, we divide molar mass by the total of the mass of the atoms making the empirical formula.
(C2H7) the mass of one carbon atoms is 12 so two atoms add up to 24. The mass of one hydrogen atom is 1 a.m.u thus 7 atoms give a total of 7 a.m.u. The sum of the two types of atoms is 24+7= 31
Molar mass=62.18
62.18/31=2.0
Hence, (C2H7) 2=C4H14
Thermal energy is dependent on the mass. If objects have a different mass then they will have a different thermal energies.