The correct answer is e. 3.57×10³
Al³+(aq) + 3e→AL(s)
4.00g of AL=4g/26.98 g/mol= 0.1483 mol
t=znF/1 where t is time in seceonds.
Z= valency number of ions of the substance or electrons which are transferred per ion
F= Faraday's constant
I = electric current in'A'CA C/s
t=(3×0.1483 mol ×96485 C/mol) /12(C15)
t=3577 second = 3.5 ×10³s
What i would say: The amount of gravitational potential energy an object has depends on its height and mass. The heavier the object and the higher it is above the ground, the more gravitational potential energy it holds. Gravitational potential energy increases as weight and height increases.
Hope this helps! :)
Answer : Hydrogen fuel cells are considered to be better than fossil fuels because of many reasons, some of them are mentioned below;
a) It is a clean fuel it does not causes any pollution to the atmosphere.
b) It more efficient than many other available fuel cells.
c) Preparation of hydrogen fuel cell relies on the free or compounded state availability hydrogen in nature, which in plenty.
d) They do not make any noise while it is being used. Hence these are considered to be quiet fuel cell.
e) They can be used for longer hours as compared to other fuel cells.
In the second diagram, the water moves out from the cell to the surroundings. This is because the surroundings of the cell have a higher concentration of salt than the cell. Hence, the water moves out of the cell to a higher concentration.
The molar mass of Na₂SO₄ -
2 x Na - 2 x23 = 46
1 x S - 1 x 32 = 32
4 x O - 4 x 16 = 64
total = 46 + 32 + 64 = 142 g/mol
the molarity of solution - 2.0 M
in 1 L of solution , 2.0 moles
Therefore in 2.5 L - 2 mol/L x 2.5 L = 5 mol
then the mass of Na₂SO₄ required = 142 g/mol x 5 mol = 710 g
