It is: 4%
The answer is 22.02 meters
40cm is 20% of 2M
40cm is 400mm
40cm
40cm
40cm times 40cm times 40cm equals 64,000cm. The volume of the cube is 64,000cm cubed or 0.064m cubed.
40
Amount of HCl is 500cm^3 of .8M HCl = .8 x 500/1000 = 0.4 mol. Volume of 10M acid to give 0.4 mol = .4/10 = 0.04dm^3 = 40cm^3 Add 500 - 40 = 460 cm^3 of water. Caution : 10M HCl is highly corrosive and should be handled with care.
The perimeter is 40cm
10M 10M 10M
48,000 cubic cm
circumference = pi*40cm