If I have a substance that is 70% pure, and want to mix it so it is 50%...?

Alright, I have rubbing alcohol that is 70% and I want to add water to it so it is 50/50. If I have 1/2 cup of alcohol, how much water do I need?

Answer:
Let x cup of water is needed.
Therefore,
0.70*0.5=0.50(0.5+x)
or,0.35=0.25+0.50x
or,0.10=0.50x
x=0.10/0.50
=0.20
Therefore 0.20 or 1/5 cup of water is to be mixed
7/10 of a cup

M1V1 = M2V2

(.70)(.5 cup) = (.50)(x)
x = 7/10 cup
70% pure + ? = 50%pure

50-70= negative 20

20 % water + 70% guessing
about 33 percent of 1/2 cup
Dont mix them just drink & enjoy.
86cc

The answers post by the user, for information only, FunQA.com does not guarantee the right.



More Questions and Answers:
  • Why the distilled water used in PH experiment had to be boiled before use?
  • Reducing Oxidation Number?
  • What special property must glassware have in order for it to be heated?
  • How do i find the number of moles of an element if the number of atoms is given?
  • What type of energy change occurs when you bake a muffin in a oven?
  • Can you use medical oxygen for welding if not why?
  • What is the percent ionization of a 0.0417 M aqueous solution of cyanic acid, HCNO (Ka = 3.5E-4)?
  • Which of the following is true of all multi-step reactions?
  • When cryolite is added to aluminium oxide to reduce the melting point, does it produce a mixture or solution?