How many liters of 5% sulphuric acid solution can be prepared from 1500 milliters of a 12 % solution?

Question

Show working please

Answer 1

If this is a chemistry problem, you can easily use V₁C₁ = V₂C₂ where V₁ and V₂ are initial and final volumes, respectively and C₁ and C₂ are initial and final concentrations, respectively.  Thus, you will have

(1.5 L)(12%) = (x L)(5%)  ...  Note: 1500 ml is changed to 1.5 L to keep units the same and those asked for in the question.

X = (1.5 L)(12%)/(5%) = 3.6 L

 

 

If this is a math problem, then you can proceed as follows: 12% of 1.5 L = 1.5 x 0.12 = 0.18 (liters of acid) 0.18/0.05 = 3.6 liters

Answer 2

This is a dilution problem. The equation for % volume concentration is volume of the solute divided by volume of the total solution:

% (v/v) = volume of solute/total volume of solution

If we dilute any given solution, the volume of solute in solution remains the same before and after adding more solvent, so we could set both concentration equations equal to each other to give

% (v/v)_c x (total volume of the solution)_c = % (v/v)_d x (total volume of the solution)_d

where c refers to the more concentrated, starting solution and d refers to the more dilute, ending solution. 

 

In the this problem, we're starting with 1500 mL of a 12% solution and ending with a 5% solution. Let's convert that percentage back to a decimal (divide by 100) and substitute these values into the equation to give

0.12 x 1500mL = 0.05 x (total volume of the diluted solution)

and solve for the unknown by rearranging the equation algebraically

total volume of the diluted solution = (0.12 x 1500mL)/(0.05) = 3600mL

Notice our volume units are conserved.