For very large numbers, it is much more convenient to use scientific notation. To do this, detect first the position of the decimal point. For whole numbers, the decimal point is place implicitly after the very last digit. Then, move this decimal point to the left until you reach to the last digit. In this case, you moved 8 places until you reach 6.4. Because the number is more than 1, the exponent would have a positive sign. Hence, the scientific notation would be 6.4×10⁸.
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:
5 L
Explanation:
We'll begin by calculating the molarity of the CaCl₂ solution. This can be obtained as follow:
Mole of CaCl₂ = 0.5 mole
Volume = 2 L
Molarity =?
Molarity = mole /Volume
Molarity = 0.5 / 2
Molarity = 0.25 M
Finally, we shall determine the volume of the diluted solution. This can be obtained as follow:
Molarity of stock solution (M₁) = 0.25 M
Volume of stock solution (V₁) = 2 L
Molarity of diluted solution (M₂) = 0.1 M
Volume of diluted solution (V₂) =?
M₁V₁ = M₂V₂
0.25 × 2 = 0.1 × V₂
0.5 = 0.1 × V₂
Divide both side by 0.1
V₂ = 0.5 / 0.1
V₂ = 5 L
Thus the volume of the diluted solution is 5 L