<span>3.75 gallons need to be drained and replaced with bleach.
Change the problem to "What amounts of a 100% solution and a 4% solution is needed to make 90 gallons of a 8% solution?" Given that, we'll use the following values.
x = amount of 4% solution.
90-x = amount of a 100% solution.
The equation to solve then becomes.
0.04 x + (90-x) = 0.08 * 90
0.04 x + 90 - x = 7.2
Add x to both sides
0.04x + 90 = 7.2 + x
Subtract 0.04x from both sides
90 = 7.2 + 0.96x
Subtract 7.2 from both sides
82.8 = 0.96x
Divide both sides by 0.96
86.25 = x
So you now know that you need 86.25 gallons of the original 4% solution and (90-86.25) = 3.75 gallons of the bleach to make the desired 90 gallons.
So simply drain 3.75 gallons from the tank and replace with bleach.</span>
<u>Answer:</u> The molarity of stock solution of luminol is 1.055 M
<u>Explanation:</u>
To calculate the molarity of solution, we use the equation:
Given mass of luminol = 14.0 g
Molar mass of luminol = 177 g/mol
Volume of solution = 75.0 mL
Putting values in above equation, we get:
Hence, the molarity of stock solution of luminol is 1.055 M
<span>Answer: an element and a compound.
An element is a pure substance formed by one kind of atoms (element).
A compound is a pure substance formed by several types of atoms(elements) that are connected by chemical bonds.
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Ch2o is the empirical formula of the substance.