tutor needed

[Guest guest]

Hello,

I had the answer to both questions but I didn't know how to solve the problem.

That's the answers that I have. You made it seem so easy to understand. Thank

You!

pharmacy_000 <pharmacy_000@...> wrote:

Hello,

I will say how I'd do these problems, but please keep in mind that I

am not a mod or a TEXTpert, so please wait for one of them to confirm

the method/answer.

Now, for these two problems I would solve them using C1 x V1 = C2 x V2

instead of alligation. C stands for Concentration and V stands for

Volume. C1/V1 means the concentration and volume you have and C2/V2

means the desired concentration and volume.

Problem #1

This problem involves ratio. 1:50 v/v means 1 ml per 50 ml (both being

ml, since this is a volume in volume solution). You use this ratio to

find out the concentration percentage. Just set it equal to x/100 ml

1 ml x ml

----- = ------

50 ml 100 ml

100 ml * 1 ml = 50 ml * x ml

x = 2 ml

Since you get the answer of 2 ml per 100 ml this would be a 2%

solution. Now use C1 * V1 = C2 * V2.

You have 100 ml of a 50% solution, so

C1 = 50% and V1= 100 ml

And you have a 2% solution and need to know how many ml

C1 * V1 = C2 * V2

50% multiplied by 100 ml = 2 % multiplied by x ml

5000 = 2x

Ans= 2500 ml

Problem #2

We will use C1 * V1 = C2 * V2 again.

The ratio we have here is 10 mg/5 ml. Let's find the concentration

percentage by setting this ratio equal to x/100 ml. Keep in mind that

percentage concentrations of w/v mean GRAMS per ml and we're working

with mg here. We're going to have to switch it to grams either at the

start or after calculating.

10 mg x mg

----- = -----

5 ml 100 ml

200 mg/100 ml =

..2 g/100 ml or .2%

Now: C1 * V1 = C2 * V2

100 ml * .2% = 500 ml * x percent

Ans: 0.04 %

>

> Two more allegation problems I need help with.

>

> #1 How many milliliters of a 1:50 v/v solution of aspirin in alcohol

> can be made from 100 mL of 50% v/v solution?

>

> #2 If 100 mL of a Choledyl elixir containing 10mg/5mL active

> ingredient (oxtriphylline) is diluted to 5oo mL, what will be the

> final strength of oxtriphylline?

>

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