A community for students.
Here's the question you clicked on:
 0 viewing
anonymous
 5 years ago
have a 700ml solution of 30% acid, needs a 50% solution of acid. How many ml of 100% acid should be added?
anonymous
 5 years ago
have a 700ml solution of 30% acid, needs a 50% solution of acid. How many ml of 100% acid should be added?

This Question is Closed

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0hmmm ok. so we're saying that the entire solution needs to be .5 (50%)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so you can solve an equation like this: (.3*700 + 1*x)/(x+700) = .5

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0so multiplying both sides by x+700, we get : .5x + 350 = x + 210

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0subtract .5 from both sides, and you get .5x + 210 = 350

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0basically  .5 is the entire fraction of acid in the total solution, hence my equation in the first step  so we know the first part of the end solution since it's given

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0700ml * .3 is pure acid

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0what you add to the solution, is also pure 100% acid, so 1*x

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0the denominator in this case will be the total amount of solution (so the original 700ml plus whatever you added)

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0and we know that the entire thing  the fraction  is .5

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0and following that logic the answer is 280ml

anonymous
 5 years ago
Best ResponseYou've already chosen the best response.0i.e. .5 = total ml acid / total ml solution (after you've added everything)
Ask your own question
Sign UpFind more explanations on OpenStudy
Your question is ready. Sign up for free to start getting answers.
spraguer
(Moderator)
5
→ View Detailed Profile
is replying to Can someone tell me what button the professor is hitting...
23
 Teamwork 19 Teammate
 Problem Solving 19 Hero
 Engagement 19 Mad Hatter
 You have blocked this person.
 ✔ You're a fan Checking fan status...
Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.